An American man was killed when a Mexican police officer opened fire on the car he was driving in Ciudad Juárez, across the border from El Paso, Texas, the Mexican authorities said on Monday.

A regional prosecutor in the state of Chihuahua, Carlos Manuel Salas, said the shooting occurred on Sunday as the officer was accompanying a staff member from the prosecutor’s office, who was serving a warrant. The two were on foot when a Mustang with New Mexico license plates suddenly accelerated in their direction, according to Mr. Salas. He said the officer opened fire as the driver tried to flee.

Mr. Salas said the officer was in custody and that the shooting, which was captured on video by a passenger in the car, would be investigated by the internal affairs division of the state prosecutor’s office. At a news conference, Mr. Salas described the incident as “regrettable” and urged the public to refrain from drawing conclusions until the investigation was complete.

But he appeared to offer a defense of the officer, whose name was not released. According to Mr. Salas, the vehicle was traveling at high speed and skidded as it approached the officer, almost hitting him. The driver was wearing a hood, he said.

“Why would you accelerate?” he asked. “Why would you drive at that speed?”

Mr. Salas argued that if something similar happened in another country, including the United States, the police would also likely respond with force.

The authorities did not identify the man who was killed, describing him only as a nursing assistant from El Paso. But Mexican news outlets reported that his name was Julián Alfredo Rodríguez Medina. News reports said the man and at least one of the two passengers in the car had family members who lived nearby.

In an interview with the news outlet El Diario, a man who identified himself as a brother of the driver, and who said he had been in the car, asked state officials to bring charges against the officer.

The man, who identified himself only as Jorge A. R., said he and the other men in the car had been out to get something to eat when they were fired on. He said they had not posed a threat and that they were at a considerable distance from the officer when he opened fire.

“At no time did we make any threats to him, nor did we yell at him, nor did we skid the car,” El Diario quoted the man as saying.

Mr. Salas, the prosecutor, said American officials had been notified about the shooting in accordance with protocol. A spokesman for the United States Embassy said in a statement that ⁠officials were “closely monitoring local authorities’ investigation into the reported killing.”

The incident is the latest in a string of violent deaths of Americans in Mexico.

Last week, a 62-year-old man from Rockford, Ill., was shot at a highway checkpoint in the state of Zacatecas that his family said was being run by a criminal organization. Days earlier, two American citizens and a Mexican national were shot dead in the state of Durango in an ambush that also left an American teenager critically injured.

Mexico’s president, Claudia Sheinbaum, has pledged to rein in the violence that has racked much of the country. While officials often point to fights between drug-trafficking cartels as the cause of the bloodshed, experts say violence involving the police is also not uncommon.

The shooting of the American on Sunday generated heated debate after the video recorded by the passenger was posted on social media. Many called for harsh consequences for the detained officer, and some commenters made death threats.

On Monday, the authorities announced an arrest in the Durango shooting, which occurred on Dec. 27. They identified the suspect as Iram Uranga Armendáriz, and they said the shooting had stemmed from a dispute over a debt related to a land deal.

Mr. Uranga has been accused of shooting two of the men in the head, then the two others — including the teenager — from behind as they tried to flee on foot. The teenager, Jason Peña, a 14-year-old from Chicago, was said to be in critical condition at a Houston hospital on Monday.

Emiliano Rodríguez Mega contributed reporting.

The U.S. military sent 11 Yemeni prisoners at Guantánamo Bay to Oman to restart their lives, the Pentagon said on Monday, leaving just 15 men in the prison in a bold push at end of the Biden administration that has left the prison population smaller than at any time in its more than 20-year history.

None of the released men had been charged with crimes during their two decades of detention. Now, all but six of the remaining prisoners have been charged with or convicted of war crimes.

There were 40 detainees when President Biden took office and resurrected an Obama administration effort to close the prison.

The Pentagon carried out the secret operation in the early hours of Monday, days before Guantánamo’s most notorious prisoner, Khalid Shaikh Mohammed, was scheduled to plead guilty to plotting the Sept. 11, 2001, attacks that killed nearly 3,000 people in exchange for a life sentence rather than face a death-penalty trial.

The handoff had been in the works for about three years. An initial plan to conduct the transfer in October 2023 was derailed by opposition from Congress.

The 11 who were released included Moath al-Alwi, a former long-term hunger striker who gained attention in the art world for building model boats from objects found at the Guantánamo prison; Abdulsalam al-Hela, whose testimony was sought by defense lawyers in the U.S.S. Cole case; and Hassan Bin Attash, the younger brother of a defendant in the Sept. 11 conspiracy case.

All of the prisoners were cleared for transfer through federal national-security review panels.

U.S. officials declined to say what the United States gave Oman, one of the most stable U.S. allies in the Middle East, and what guarantees it received in exchange. By law, the military cannot send Guantánamo prisoners to Yemen because, as a nation caught up in a brutal civil war, it is considered too unstable to monitor and rehabilitate returnees.

The United States has typically paid host countries stipends for housing, education, rehabilitation and to monitor the activities of the men. The United States has also asked receiving countries to prevent the former Guantánamo detainees from traveling abroad for at least two years.

Few details about the rehabilitation program have emerged from Oman, an insular nation led by a sultan. Saudi Arabia has shown its reintegration center for Guantánamo detainees to reporters and scholars, but Oman has not.

U.S. officials have called Oman’s program “well rounded” and designed to help the Yemenis return to society with jobs, homes and families, many through arranged marriages.

The Obama administration sent 30 detainees to Oman from 2015 to 2017. One man died there, but the rest were sent home — 27 to Yemen and two to Afghanistan, according to a State Department official, who spoke on the condition of anonymity because of the sensitivity of the diplomatic negotiations.

Many of the Yemenis married and had children in Oman and were repatriated with their families.

Word of the successes reached the Yemeni prisoners at Guantánamo and made Oman a desired resettlement country, said George M. Clarke, a lawyer for two of the men who were transferred this week.

“It’s not just culturally compatible,” Mr. Clarke said. “It’s because they are given reasonably decent freedom, and they are properly integrated into society in a successful way. And that’s what makes resettlement work.”

The men sent to Oman were captured by allies of the United States or taken into U.S. custody between 2001 and 2003. Mr. Clarke said they were eager to rejoin a world of cellphones and internet access.

“They want to live their lives,” said Mr. Clarke, who represents Tawfiq al-Bihani and Mr. Bin Attash. “They want to get married. They want to have kids. They want to get a job and have normal lives.”

In October 2023, a military cargo plane and security team were already at Guantánamo Bay to transport the 11 detainees to Oman when congressional objections led the Biden administration to abort the mission, which finally took place this week.

At the time, the prisoners who left this week had already undergone exit interviews with representatives of the International Committee of the Red Cross, and guards had taken away the personal belongings that would travel with them.

For the next year, Tina S. Kaidanow, the Biden administration’s envoy for Guantánamo affairs, kept the deal viable through negotiations, travel and meetings both within the United States government and with the receiving country, the State Department official said. Ms. Kaidanow died in October.

Three other prisoners at Guantánamo are eligible for transfer, including a stateless Rohingya, a Libyan and a Somali.

In addition, the State Department had been trying to find a nation to receive and provide health care for a disabled Iraqi man who has pleaded guilty to commanding irregular forces in wartime Afghanistan. U.S. officials have a plan to send him to a prison in Baghdad, but he is suing the Biden administration to thwart that transfer on the grounds that he would be at risk in his homeland.

Guantánamo’s detention zone today is an emptier, quieter place than it once was.

The remaining 15 detainees are held in two prison buildings with cell space for about 250 prisoners.

The prison opened on Jan. 11, 2002, with the arrival of the first 20 detainees from Afghanistan. At its peak, in 2003, the operation had about 660 prisoners and more than 2,000 troops and civilians commanded by a two-star general. The detainees were mostly held in open-air-style cells on a bluff overlooking the water while the prisons were built.

The operation now has 800 troops and civilian contractors — 53 guards and other staff members for every detainee — and is run by a more junior officer, Col. Steven Kane.

Most of those sent away were repatriated to countries that included Afghanistan, Algeria, Kenya, Malaysia, Morocco, Pakistan, Tunisia and Saudi Arabia. In addition, Belize accepted a Pakistani man who pleaded guilty to war crimes and became a government cooperator. That man, Majid Khan, has been joined by his wife and daughter there.

A top U.S. envoy who helped broker the cease-fire between Israel and Hezbollah issued reassurance on Monday that Israel would withdraw fully from southern Lebanon, as called for in the fragile 60-day truce deal that paused the bloodiest war between the two sides in decades.

Speaking to reporters in Beirut, the Lebanese capital, the envoy, Amos Hochstein, said that Israeli troops had pulled out on Monday from the southern town of Naqoura. In a statement, the Lebanese military said it had redeployed in the town, after the Israeli withdrawal.

“These withdrawals will continue until Israeli forces are fully out of Lebanon,” Mr. Hochstein said after meeting with senior Lebanese officials. “There’s been much progress in recent days, and I expect to see additional progress being made in the days to come.”

Although the truce reached in late November continues to hold, there is growing frustration among Lebanese and Israeli officials about the pace at which the cease-fire agreement is being carried out, with the deadline fast approaching for the terms to be fulfilled.

Mr. Hochstein did not specify when Israeli troops would withdraw completely from Lebanon, and it remains uncertain whether the cease-fire agreement will be fully in place by the end of the 60-day period.

The deal ended a 14-month conflict between Israel and Hezbollah, a powerful militant group in Lebanon that began firing rockets into Israel in support of the Hamas-led attack on Israel on Oct. 7, 2023. Hezbollah and Hamas are backed by Iran, part of its network of regional proxies.

After Israel went on the offensive against Hezbollah in September last year, the violence killed nearly 4,000 people in Lebanon and displaced over a million others. The fighting has also seriously weakened Hezbollah, with much of its leadership wiped out.

Under the terms of the cease-fire, Israeli troops have until Jan. 26 to pull out of Lebanon. Hezbollah militants are required in tandem to withdraw to north of the Litani River in southern Lebanon, and the Lebanese military is expected to deploy in force along the border.

So far, however, the Israeli military has withdrawn from just three of the dozens of areas in southern Lebanon where it continues to hold positions, a figure that includes the Monday withdrawal from Naqoura, where a U.N. peacekeeping mission is based.

Amid accusations of cease-fire violations by both sides, Lebanon has also reported to the U.N. Security Council that Israel had launched over 800 “ground and air attacks” since the cease-fire came into effect.

In turn, Israel’s defense minister, Israel Katz, accused Hezbollah and the Lebanese state on Sunday of failing to meet the terms of the cease-fire agreement, warning that Israel may be “forced to act” if progress is not made.

“This is not an easy process to implement; it’s a difficult process,” Mr. Hochstein conceded at the news conference on Monday.

Hezbollah’s new leader, Naim Qassem, threatened in a speech on Saturday that his group might begin attacking Israel again if the country’s troops did not fully withdraw from southern Lebanon before the 60-day period ends.

“When we decide to do something, you will see it directly,” he said.