First use of the low-flying, lumbering turboprop AC-130 followed the fiercest daylight raids of the offensive and marked a stepping-up of attacks on Taliban bases and leadership.

It also signaled U.S. confidence that more than a week of attacks by ship-launched cruise missiles and high-flying jets had greatly eased the threat from Taliban air defense.

U.S. Secretary of State Colin Powell, in neighboring Pakistan to shore up support for the U.S.-led campaign, said Afghanistan's Islamic regime was "under enormous pressure" but refused to say whether he thought it near collapse.

Tuesday's fresh waves of air strikes targeted the Taliban at multiple fronts _ military bases and airports outside the capital of Kabul, Taliban leaders' southern base city of Kandahar and the key northern city of Mazar-e-Sharif.

The attacks at Kandahar left the Taliban unsure even what hit them. Taliban leaders believed it was helicopter gunships that had entered the war for the first time, Taliban Information Ministry official Abdul Himat said.

Himat claimed 13 civilians died in the assault at Kandahar. The claim was impossible to verify independently.

In Washington, a defense official confirmed the overnight attack was led by an AC-130, marking the first acknowledged use of special-forces aircraft in the now 10-day-old offensive. The official spoke on condition of anonymity.

Previous raids had targeted anti-aircraft artillery sites and other military installations with the aim of making the skies safe for aircraft like the AC-130. The Taliban are believed to still hold an unknown number of shoulder-fired Stinger missiles capable of bringing down aircraft, however.

High-firepower AC-130s typically are used to support ground forces trained for small-unit operations. There was no word whether the gunship's deployment meant special forces had entered the battle on the ground.

Aiming to make the skies safe, U.S. forces have made particular targets out of airports in Taliban territory throughout the campaign. Attacks put the Jalalabad airport in eastern Afghanistan out of commission almost from the start.

Other strikes have pounded Taliban jets at Kabul and the sprawling airport complex at Kandahar, which holds at least 300 housing units of bin Laden's followers.

The only other major airfields in Taliban territory, at Shindand in southwestern Afghanistan and in Herat, have also taken repeated strikes.

The United States launched the air campaign Oct. 7 to root out bin Laden _ the top suspect in the Sept. 11 terror attacks on the United States _ and to punish Afghanistan's rulers, the Taliban Islamic militia, who harbor him.

Defense Secretary Donald H. Rumsfeld, speaking at the Pentagon, suggested Monday that better targeting information would allow U.S. airstrikes to soon start targeting Taliban front-line positions facing Afghan opposition fighters in the northeast.

Taking advantage of the massive assaults, opposition forces on the ground claimed Monday to have advanced within miles of their former stronghold of Mazar-e-Sharif.

Tuesday's U.S. attacks at Mazar-e-Sharif left two people dead, the Afghan Islamic Press said in a report from Islamabad.

The Taliban, which holds 90 percent of the country, wrested away control of the major northern city in 1998. The coalition of opposition forces holds the rest.

Pakistan, which has agreed to lend logistical support for the campaign, has pressed for the U.S. and British offensive to avoid directly helping opposition troops. Pakistan fears the northern alliance, its longtime opponent, will seize power from the Taliban.

With Powell beside him, Pakistani President Gen. Pervez Musharraf told an Islamabad news conference Tuesday that the military strikes should "short and targeted."

Powell found himself struggling to calm tensions between Pakistan and India after new fighting in the disputed province of Kashmir.

The United States had been trying to head off just such a flare in hostilities between the longtime rivals, fearing it would hinder key ally Pakistan from the campaign in Afghanistan.