Defense Secretary Donald Rumsfeld says U.S. troops are killing Taleban and al-Qaida forces who do not surrender. Mr. Rumsfeld's disclosure coincides with word that a top aide to terrorist leader Osama bin Laden has been killed by U.S. bombs.

The aide is Mohammed Atef, an Egyptian who was Osama bin Laden's chief advisor on military matters and a suspected planner of the September 11 terrorist attacks in the United States.

U.S. officials say they believe he was killed in airstrikes near the Kabul area in Afghanistan in recent days.

The disclosure comes as Defense Secretary Donald Rumsfeld reveals U.S. special forces are interrogating Taleban and al-Qaida officials being held by the opposition. He will not identify them but hints some may be senior figures.

Mr. Rumsfeld also disclosures U.S. troops on the ground in Afghanistan have killed some Taleban and al-Qaida soldiers. "They are killing Taleban that won't surrender and al-Qaida that are trying to move from one place to another...The total effect of it is that it is becoming less and less hospitable for al-Qaida and Taleban to be around," he said.

Still, he acknowledges al-Qaida leader Osama bin Laden remains at large. Mr. Rumsfeld has previously said the terrorist may escape from Afghanistan. But he remains confident Osama bin Laden will eventually be caught.

Mr. Rumsfeld spoke to reporters during a trip to the Midwest where he was visiting a naval training facility near Chicago.