WASHINGTON - President Bush sternly rejected a Taliban offer to discuss handing over Osama bin Laden to a third country as U.S. jets began a second week of bombing yesterday.

"They must have not heard. There's no negotiations," the president said.

Returning to the White House after a weekend at the Camp David retreat, Bush reiterated four conditions the Taliban must meet before bombing will be stopped.

"All they got to do is turn him [bin Laden] over, and his colleagues and the thugs he hides, as well as destroy his camps and [release] the innocent people being held hostage in Afghanistan," Bush said.

The latter was an apparent reference to eight foreign aid workers imprisoned in Afghanistan. The administration had avoided calling them "hostages." In his speech to a joint session of Congress on Sept. 20, Bush said they had been "unjustly imprisoned." A White House spokeswoman said she believed it was the first time that Bush had publicly used the word "hostage."

Bush rejected any negotiations as a Taliban leader suggested the Afghan government would be willing to discuss surrendering bin Laden to a third country if the United States provided evidence of his guilt and stopped bombing.

"There's no need to discuss innocence or guilt," Bush said. "We know he's guilty." While Bush returned to the White House, his Cabinet members mobilized at home and abroad.

National Security Adviser Condoleezza Rice sought to quell fears that the terrorists might have crude nuclear weapons. A defense official said last week that if the terrorists have obtained nuclear material, they might be able to make a weapon that could spread radiation without a destructive explosion. "We have no credible evidence at this point of a specific threat of that kind," Rice said on CBS' 60 Minutes last night.

Attorney General John Ashcroft said investigators want to question about 190 people who might have knowledge of terrorism.

And Secretary of State Colin L. Powell left for a high-priority diplomatic mission to Pakistan and India aimed at keeping tensions between those nations from further complicating the military campaign in neighboring Afghanistan.

Overseas, a U.S. military official said the bombing of Afghanistan has entered a "cleanup mode."

U.S. warplanes have destroyed nearly all of the targets originally assigned to them, including militant training camps and weapons storage areas, the captain of the USS Enterprise aircraft carrier said yesterday. His identify could not be disclosed under military rules for covering the operation.

In the latest raids, U.S. jets destroyed Kabul's Chinese-built international telephone exchange, severing one of the last means of communication with the outside world. Residents also said the capital's historic Mogul-style Balahisar Fort, built in the early 20th century, was in ruins. The report could not be confirmed because security kept outsiders from the area.

Other targets included the cities of Mazar e Sharif, Kandahar, Jalalabad and Herat, said the Taliban Information Ministry. Explosions were heard late yesterday well north of Kabul in the direction of the front lines between opposition and Taliban fighters.

One strong detonation about midnight triggered what appeared to be a series of secondary explosions.

A nighttime attack on the Taliban headquarters in Kandahar plunged the city into darkness and enveloped it in dust yesterday, the private Pakistan-based Afghan Islamic Press said. The main target appeared to be military headquarters, it said.

A commander in the coalition battling the Taliban said opposition leaders have organized a 2,000-strong security force to maintain law and order in Kabul if they capture the city.

The lightly armed force would secure the city until a new government can be established, Gen. Haji Almaz Khan said in Charikar, an alliance stronghold 25 miles north of Kabul.

The United States and its partners have been urging the opposition to avoid launching an all-out attack on Kabul until a broad-based government can be formed to replace the Taliban. Most of the Taliban are ethnic Pashtun; the alliance is dominated by ethnic Tajiks and Uzbeks.