American warplanes pounded barracks, garrisons and troop encampments across Afghanistan yesterday in the heaviest airstrikes yet against ground forces of the Taliban regime, the protectors of the suspected terrorist Osama bin Laden and his network.
As long-range bombers and fighter jets soared over the mountains to hit Taliban positions near Kabul, President Bush announced multimillion-dollar rewards for the capture of Mr. bin Laden and 21 other international terrorists, including several of his lieutenants.
Concerned about the possibility of more terrorist attacks on American soil in retaliation for the bombing, the White House also persuaded five major American television news organizations to agree yesterday to edit broadcasts of any more videotaped statements from Mr. bin Laden or his organization, for fears that they contained coded messages.
The tighter controls over information in the government's declared war on terrorism came as federal law enforcement officials said that a 35-year-old woman in South Florida had tested positive for anthrax. She was a co-worker of two other victims of what authorities now believe was a criminal act. Authorities said they do not know whether the anthrax reports have any connection with the events of Sept. 11.
The airstrikes in Afghanistan followed three days of bombing in which troops in the field were largely spared as planes concentrated on knocking out air defenses and striking command centers, airfields and Mr. bin Laden's terrorist training camps, Pentagon officials said.
Tonight, one day after the Pentagon declared it essentially controlled the skies over Afghanistan, more long-range bombers -- some using cluster bombs -- and a smaller number of fighter jets flew in to hit Taliban positions.
''The prime focus was garrisons, bivouac areas, maintenance sites, troop-type facilities,'' a Defense Department official said. ''It was substantial.''
The American military operation suffered its first casualty yesterday when an American soldier was crushed between two military vehicles at the Khanabad air base near Karshi, Uzbekistan, some 100 miles north of the Afghan border. The Pentagon later said in a statement that the soldier was in critical condition after being airlifted to an air base in Incirlik, Turkey, but did not identify him or his unit.
Pentagon officials also acknowledged yesterday that an American cruise missile might have been responsible for the death of four security guards at a United Nations-affiliated organization in Kabul.
Defense Secretary Donald H. Rumsfeld said on Tuesday that the Taliban's own antiaircraft fire might have been responsible. But yesterday a Pentagon official said that the United States had fired four cruise missiles at a nearby radio tower, but that only three of them hit their target.
The Pentagon failed for the first time since strikes started on Sunday to give a briefing on its actions. Officials noted a memorial service for victims killed in the Sept. 11 attack on the Pentagon is planned, with President Bush scheduled to attend. The decision not to hold a briefing yesterday was a break with longstanding Pentagon practice.
Victoria Clarke, the Pentagon spokeswoman, would say only, ''We chose not to have a briefing today.'' During the Persian Gulf war, military officers gave daily televised briefings and enjoyed a certain international celebrity.
From the start of its Afghan campaign, Bush administration officials have cautioned that they did not expect to win the war from the air. But a critical aim of the air campaign has been to weaken the Taliban military forces -- and the Arab fighters allied with them who were recruited by Mr. bin Laden -- so that American and British special forces can conduct military operations within Afghanistan.
Pakistani officials said today that American military personnel were in the country, but stressed that Pakistan was committed to providing the United States only with logistical support for its strikes on Afghanistan and the forces were not combat troops.
The Pentagon is planning to conduct risky missions with helicopter gunships and special operations forces, officials have said, in order to search out and attack forces allied with Mr. bin Laden.
A senior British defense official said on Tuesday that a main purpose of the strikes conducted so far was to ''condition the environment'' so that there will be ''less risk of damage to our own people, our own aircraft.''
Yesterday ''conditioning the environment'' meant blasting an array of targets near Kabul. Observers said it was the biggest attack near the Afghan capital. The precise targets were not known, but explosions were reported in the vicinity of the Taliban military academy and artillery units.
There were also more strikes near Kandahar, which is the political base for the Taliban. These included attacks at the compound for Mullah Muhammad Omar, the one-eyed cleric who is the supreme leader of the Taliban, and the city's airport.
A military base at Shamshaad, near the border with Pakistan, also came under attack, apparently one of the ground force targets on the American military's list.
The attacks involved about 10 B-52 and B-1 bombers, which took off from the island of Diego Garcia. They dropped ''area munitions,'' including CBU-89 Gators, which are 1,000-pound cluster bombs.
''We're putting lots of bombs on them,'' one senior military officer said.
B-2 bombers, which carry satellite-guided munitions designed to go after fixed targets, were not scheduled to be used. Neither were cruise missiles.
The intensity of yesterday's effort against the ground troops contrasted with the early days of the campaign. According to American military officials, the sole ground force attacked during the first two days of the war was a garrison of fighters recruited by Mr. bin Laden that has fought with the Taliban. Its garrison, near the northern town of Mazar-e-Sharif, has been struck twice.
According to the Northern Alliance, the anti-Taliban group that has been fighting the regime, the fighters at the garrison included Arabs, Chechens and members of the Islamic Movement of Uzbekistan.
The Northern Alliance, which controls up to 10 percent of Afghanistan from its bases in the north of the country, said the United States is working quietly with its forces.
Although reporters who are with the Northern Alliance on its front lines have seen no sign of the presence of foreign troops, Haron Amin, a special envoy for the Northern Alliance, said in an interview that American and British special forces are stationed in territory controlled by his group.
Mr. Amin said that the American and British commandos have been conducting reconnaissance missions and working with the rebels.
The Northern Alliance, Mr. Amin said, has had sympathizers in Kabul and other cities provide reports about the effectiveness of American bombing strikes.
''The U.S. can see from satellites, but they don't know exactly who was killed,'' Mr. Amin said.
In another development, officials said that an American aircraft began radio broadcasts in Afghanistan. Dubbed ''Commando Solo,'' and operated by the Pennsylvania Air National Guard, it is broadcasting on the frequency that had been used by a Taliban station until its radio tower was destroyed by cruise missiles.
The American and British do not have the only forces in Afghanistan. The French have deployed between 20 and 30 military intelligence officers, according to a Western official. The French are seeking more information before deciding whether to provide soldier mountaineers for the next and largely covert phase of the military operation in Afghanistan.
As the American and British military operation has progressed and the United States has begun to focus more on the eventual use of ground forces, there has been renewed attention to bases in the region.
In Pakistan, an official said that United States forces will be able to use at least two bases, which he identified as Pasni, a port city where a small airport is located, and Jacobabad, where there is an air base.
The Pakistani official said he expected that 2,000 to 3,000 American military personnel might be deployed at those bases.
The installations are not in the Pashtun areas of Pakistan, where there is considerable popular resentment about the American military operation against the ethnic Pashtun in Afghanistan. A Pentagon official confirmed that Jacobabad was one of the locations.
In lieu of a press briefing, the Pentagon issued a three-paragraph statement describing in general terms what type of attacks were carried out on Tuesday. The Pentagon said six targets had been struck, using between five and eight land-based bombers and 8 to 19 naval jets.
The targets hit included airfields, air defense site, the previously struck garrison near Mazar-e-Sharif and infrastructure of Al Qaeda, Mr. bin Laden's terrorist network.
The statement also mentioned that two C-17's had dropped 35,000 rations.