WASHINGTON - As the United States pounded targets in Afghanistan for a fourth day, U.S. forces launched their heaviest attack against the capital, Kabul, igniting explosions around a Taliban military academy, artillery units and suspected terrorist camps.

With the United States claiming air supremacy in its effort to root out Osama bin Laden's terrorist network, U.S. planes and missiles also reportedly hit the Taliban stronghold of Kandahar and a Taliban military base in Shamshaad, near the Pakistani border.

At the same time, two Air Force C-17 transport planes dropped for a third day about 35,000 packets of food rations for Afghan civilians.

Officials said the Pentagon is adding 5,000-pound "bunker-buster" bombs to the mix of weapons that are targeting the Taliban military and is laying the groundwork for commando raids.

The aerial attacks yesterday moved the U.S.-led campaign closer to the start of ground operations against the al-Qaida terrorist network and the Taliban regime that has protected it.

Publicly, the Pentagon offered no information about yesterday's attacks, though some officials said "leadership targets," such as command-and-control facilities in underground bunkers near Kandahar, were to be hit with 5,000-pound laser-guided bombs. The Taliban's headquarters are in that southern Afghanistan city.

The officials said they could not verify immediately that the attacks were conducted as planned. Defense Secretary Donald H. Rumsfeld has hinted that more attacks would be aimed at such targets.

One U.S. official, speaking on condition of anonymity, said that two men related to the Taliban's supreme leader, Mullah Mohammed Omar, were killed in bombing strikes on the leader's home in Kandahar.

U.S. officials said warplanes would also begin dropping cluster munitions, which dispense smaller bomblets, for use against armored vehicles, troop convoys and other moving and stationary targets.

Beginning tomorrow, NATO will patrol skies over the United States, using AWACS surveillance aircraft from Germany that will relieve U.S. planes that have been dispatched to Afghanistan. NATO is aiding the United States in its campaign against terrorism under the alliance's Article 5, which states that an attack on one member of NATO is an attack on all.

Noting the historic nature of NATO's mission, President Bush praised it for helping patrol U.S. airspace with early warning spy planes: "This has never happened before - that NATO has come to help defend our country - but it happened in this time of need, and for that we're grateful."

The State Department offered further evidence that it has made progress in building an international coalition to fight terrorism. It said dozens of potential terrorists in 23 countries have been arrested or detained overseas: 10 in Europe, one in East Asia, four in Africa, seven in the Middle East area and one in Latin America.

Officials from Pakistan and the United States said Pakistan is letting Washington use two of its air bases to support military operations over Afghanistan but not to launch air or ground attacks.

In addition, Richard Boucher, department spokesman, said the administration knows of 111 countries that have modified banking regulations, frozen assets or taken other steps to curb the flow of money to terrorists.

In a reminder that officials fear another terrorist attack, Vice President Dick Cheney worked at an undisclosed secure location for a fourth straight day. Cheney has not been seen in public since the bombing campaign began Sunday, a highly unusual security caution.

An ABC News poll released yesterday found that nine out of 10 Americans support the airstrikes in Afghanistan. The poll, taken Monday and Tuesday, has a margin of error of plus or minus 3 percentage points.

Yesterday, Bush unveiled a list of the 22 most wanted terrorists, topped by bin Laden, two top deputies and members of his al-Qaida terrorist network who have been implicated in bombings overseas against U.S. interests. The list is intended to demonstrate that the campaign against terrorism extends beyond those responsible for the Sept. 11 terrorist attacks on the United States. "Terrorism has a face, and today we expose it for the world to see," Bush said at FBI headquarters. "We list their names, we publicize their pictures, we rob them of their secrecy."

Today, Bush is to deliver the principal address at a memorial for the 189 people killed in the attack on the Pentagon. After a confrontation with members of Congress earlier in the week, the president backed away yesterday from his earlier decision to confine classified briefings on the terrorism campaign to eight top members of Congress. The president agreed to allow some briefings for members of the armed services and foreign relations committees as well.

The "bunker-buster" bomb the Pentagon is adding to its weaponry in Afghanistan was developed during the gulf war for striking deeply buried targets. It was used in 1991 against a bunker complex in Iraq; two years ago, a version with an improved guidance system was put into production.

The B-2 stealth bomber is capable of dropping the improved version of the bomb. B-2s have flown missions over Afghanistan and dropped 2,000-pound satellite-guided bombs.

At Whiteman Air Force Base in Missouri, Brig. Gen. Tony Przybyslawski, commander of the 509th Bomb Wing, said yesterday that six B-2s flew from Whiteman to their targets in Afghanistan, then continued to the Indian Ocean island of Diego Garcia, where fresh crews took over for the return flights to Whiteman. The 44-hour combat missions were the longest in history, he said.

The next phase of the U.S.-led military campaign will probably include secret raids by small groups of Army special operations forces - perhaps Rangers or Green Berets - ferried into Afghanistan by low-flying helicopters to rout out al-Qaida or Taliban leaders, military analysts said.

Some news reports have indicated that small teams of British and U.S. special reconnaissance teams had been inside Afghanistan before this week's airstrikes began. The next deployment is expected to be much larger now that the strikes have made freer movement of troops possible.

The Pentagon released a brief statement with minimal details about Tuesday's bombing raids, the smallest since attacks began Sunday. U.S. forces struck six military targets in Afghanistan, using between five and eight bombers and eight to 10 carrier-based Navy strike aircraft, it said. The targets Tuesday were airfields near Kabul in the east and Herat in the west; surface-to-air missile emplacements near Kabul and Jalalabad, and an al-Qaida training camp near Kandahar, the Pentagon said.

In addition, a maintenance facility at a Taliban army garrison near Mazar-e Sharif was struck for a second time. Unlike in the first two days of attacks, Tomahawk cruise missiles were not fired Tuesday and none were planned to be used yesterday, according to military sources. The focus of the air campaign over Afghanistan is turning to more elusive targets after opening salvos neutralized the Taliban's meager air defenses. Among priority targets are deeply buried command-and-control facilities associated with Taliban leaders' compounds.

U.S. officials said bin Laden's al-Qaida network has been bolstering Islamic insurgencies in Indonesia, the Philippines and Malaysia as Southeast Asia has become an operational hub for the terrorist network. Secretary of State. Colin L. Powell said no military action is being planned against the terrorist infrastructure in these countries.