The U.S. attacks on Afghanistan claimed their deadliest tally yet when a strike on Kabul killed 22 Pakistani militants Wednesday.

The heavy day-and-night pounding of the Afghan capital marked a return of large numbers of U.S. warplanes to Kabul after three days of attacks concentrated on Taliban front lines to the north.

One of the U.S. bombs struck a house in Kabul Tuesday while fighters from the banned Harakat ul-Mujahedeen were meeting there, according to Muzamal Shah, a senior official of the group. The 22 dead included several senior commanders, Shah said.

Some of the band had crossed into Afghanistan since the U.S. bombing began to help "devise a plan for fighting against America," Shah said.

Harakat ul-Mujahedeen, or "Movement of the Holy Warriors," is one of the largest militant organizations fighting Indian soldiers in the disputed Kashmir region. It was declared a terrorist organization by United States years ago, and was among 27 groups and individuals whose assets were frozen by the United States, Pakistan and other countries after the Sept. 11 terrorist attacks in the United States, in which Washington suspects bin Laden.

On Wednesday, a group of men brought the bodies of 11 of the dead Pakistani fighters to Afghanistan's border with Pakistan, hoping to bury them in their homeland. The Pakistani border guards refused to let them cross, according to the Taliban's local security chief, Noor Mohammed Hanifi.

"They said, 'You wanted to fight with the Taliban then you can bury your dead in Afghanistan,"' Hanifi said.

Turned back at the official crossing, the group slipped the bodies across the border elsewhere, witnesses said. Some of the dead had come from the western Pakistan border towns of Chaman and Dera Ismail Khan and the central port city of Karachi.

In other attacks-related developments:

--The Pentagon disclosed new details about Saturday's commando raids into Afghanistan, in which an airfield was seized and documents taken from a Taliban compound that included Taliban leader Mullah Mohammed Omar's home. There was one accident: An Army MH-47 helicopter struck an unknown barrier while it was taking off, shearing off its front landing gear, Pentagon spokeswoman Victoria Clarke said. But the chopper returned safely and no one aboard was injured. The wheels from the helicopter were displayed on television by the Taliban, which claimed to have shot down an American helicopter.

--The Pentagon vowed to flush out any Afghan fighters who hide in residential areas to escape aerial attacks. The promise came even as the Pentagon acknowledged its bombs accidentally struck civilian sites. Rear Adm. John Stufflebeem said that to "smoke out" enemy soldiers, the U.S. might send in commandos or other ground forces.

In Afghanistan, attacks persisted late Tuesday and early Wednesday, with U.S. jets striking targets around Kabul and military installations at the Taliban headquarters in Kandahar, Taliban spokesman Mullah Amir Khan Muttaqi said.

In northeast Afghanistan, thousands of of anti-Taliban troops and weapons were waiting in the strategic Panjshir Valley, ready for an attack on Kabul, northern alliance deputy brigade commander Haji Bari said at a front-line post at the Rabat district.

"We're waiting for the order," he told The Associated Press against a background of crackling artillery and machine-gun fire.

For the moment, however, alliance fighters are pulling back their positions to put their troops at a safe distance from U.S. bombs striking front-line Taliban positions, he said. On Monday, he said, three U.S. bombs landed behind alliance lines but caused no casualties.

American support for the northern alliance -- especially along the Kabul front -- threatens to strain relations between the United States and Pakistan, perhaps America's strongest supporter in the anti-terrorism campaign within the Muslim world.

Pakistan had close ties to the Taliban before the Sept. 11 attacks. Pakistan also fears the alliance -- a factious, northern-based coalition mostly of minority ethnic Tajiks and Uzbeks -- would never be accepted by the Pashtun majority.

Pakistan has called for a broad-based, multiethnic government to replace the Taliban. On Wednesday, about 1,000 Afghans, including tribal leaders, clerics and supporters of the former king Mohammad Zaher Shah, gathered in the Pakistani border city of Peshawar to discuss prospects for a new government.

Pakistani President Pervez Musharraf told a Lebanese television station Tuesday that Kabul should be declared a neutral zone, "because I see that maybe atrocities (could) start in Kabul" if the alliance recaptures the city.

The Associated Press contributed to this report.