U.S. Marines became hunters Saturday, toting photographs of wanted terrorists on their search of southern Afghanistan for Taliban and Al Qaeda leaders feared to have escaped Kandahar during the militia's surrender.

Marines patrolled key roads around Kandahar carrying photographs of "key terrorists," spokesman Capt. Stewart Upton said at their base southwest of the city. Upton said they were generally leaving alone Taliban fighters who have blended back into the civilian population. 

"We are searching for members of the Al Qaeda, not regular Taliban soldiers," Upton said in reference to bin Laden's group of foreign fighters. "We hope the Taliban lays down his arms and goes his merry way."

More than 200 Arabs loyal to Usama bin Laden were still holding out at the Kandahar airport and refusing to surrender, tribal officials said via telephone from Pakistan.

Even though Kandahar was freed from Taliban control, it is reported to be tense, with the rival armed groups that filled the authority vacuum occasionally exchanging gunfire in their fight for control of key parts of the southern city.

Negotiations were reportedly under way to establish a civil administration and avoid an outbreak of factional fighting. 

Hamid Karzai, the leader of the U.N.-backed interim council that will run Afghanistan for six months, called on his countrymen to participate in the hunt for bin Laden and supreme Taliban leader Mullah Mohammed Omar, whose locations remain a mystery. 

"We will make sure we will get rid of terrorism. We want to finish terrorism in Afghanistan and in the world," Karzai said.

Neighboring Pakistan sent more forces and helicopters to its border with Afghanistan to prevent Taliban or Al Qaeda troops from entering that country. 

Meanwhile, American warplanes bombed the remote mountains around the Tora Bora cave and tunnel complex where locals believe bin Laden, the prime suspect in the Sept. 11 attacks, could be hiding. However, the bombing was far less intense than in recent days.

U.S. sailors and Marines in the Arabian Sea have searched some 200 vessels in the last two weeks for fleeing pro-Taliban fighters, Pentagon spokesman Lt. Col. Dave Lapan said. Pakistan's chief spokesman, Gen. Rashid Quereshi, said the country had sent extra troops and helicopters to border posts to cut off possible escape routes. He denied speculation that bin Laden and Omar could have slipped into Pakistan. 

In other developments: 

— John Walker, an American captured along with Taliban fighters, is being held by Marines in Afghanistan and will be handed over to U.S. civilian authorities as soon as possible, though it has not been decided how his case will be handled, the Pentagon said. Marine Capt. Stewart Upton said that Walker is currently considered a "Battlefield detainee."

—Pakistani police seized a border area, moving a mile past the frontier crossing at Chaman, south of Kandahar. Pakistan says the area belongs to it but that it withdrew during the wars of the 1980s to create a buffer zone. 

—The family of Ayman al-Zawahri, the top aide to bin Laden, published a death notice in Egypt's top newspaper Al-Ahram saying his wife and children were killed in Afghanistan. They were reportedly killed in a U.S. airstrike.

In Kandahar, rival factions — some under former governor Gul Agha and others under Kandahar powerbroker Mullah Naqibullah — took control of parts of the city, waiting for a tribal council to sort out a new administration. "Everything is ready for a commission of tribesmen," Karzai said. 

A Kandahar resident, Abdul Mateen, said armed men were roaming around the streets and that many residents stayed indoors, fearing an outbreak of fighting. The currency exchange market and virtually all shops were closed Saturday, although a few food stores and small restaurants remained open, Mateen said. 

Agha, whose men took over the city hall and governor's residence, has refused to recognize the authority of his rival, Naqibullah. 

Pakistani border guards refused to let journalists cross into southern Afghanistan, saying the situation was too volatile. 

Andrew Card, President Bush's chief of staff, said Friday that U.S. officials were "pretty sure" Omar was still in Kandahar, which the Taliban agreed to surrender on Friday, then fled before the opposition took control. 

Khalid Pashtun, a spokesman for Agha, claimed Omar was under the "protection" of Naqibullah. 

But Karzai said reports that Omar had been captured were "all lies." 

Naqibullah and Karzai jointly negotiated the Taliban surrender of the southern city, but Agha felt he had been cut out of the deal. Agha's tribesmen had been fighting around the Kandahar airport and controlled part of the road to Pakistan. 

Agha and Naqibullah have had strained relations for years since Naqibullah refused to side with Agha against the Taliban in the early 1990s. 

There was little bombing around the caves of Tora Bora in eastern Afghanistan, where tribal fighters have been battling Al Qaeda members hiding in the mountains. 

A B-52 dropped several 500-pound bombs in the afternoon, and Al Qaeda fighters fired mortars at a road leading to the front line to prevent tribal forces from advancing. 

Also Saturday, U.S. Marines buried an Afghan anti-Taliban fighter with a 21-gun salute after he was killed by an errant American bomb. 

The Afghan, who was not identified, was one of six anti-Taliban fighters killed on Wednesday when an Air Force B-52 dropped a one-ton satellite-guided bomb that also killed three Army Green Berets soldiers. Twenty Americans and 18 Afghans were wounded. 

"This is not a man we knew, or a man we served with, but we are tied together by a common goal — freedom," Marines intelligence officer Maj. Beau Higgins said in a eulogy. 

Four of the Americans wounded in the accident spoke to reporters at a U.S. military hospital in Landstuhl, Germany, where they were being treated. 

Capt. Jason Amerine of the U.S. Army 5th Special Forces Group said his team had been on a hilltop directing airstrikes against a Taliban position about two miles away when the bomb hit. "Out of the blue, our position exploded," the 30-year-old Honolulu native said. "I was thrown over the side of the hill." 

It was unclear when the remains of the three Americans killed would be flown home from Germany. 

"We're all pretty numb," Amerine said. "Our prayers are with our wounded and with the families of the men who didn't survive." 

The Associated Press contributed to this report.