TERROR / Airstrike may have killed bin Laden's No. 2

(CNN) - A CIA airstrike on a building in Pakistan may have killed Osama bin Laden's most-trusted aide, sources said.

The building where Ayman al-Zawahiri was thought to be is in Damadola, a small village near the Afghan border.

There has been no confirmation that al-Zawahiri, 54, was killed in the attack Friday. However, sources say there was intelligence suggesting he was in the building at the time of the strike.

Pakistani officials were at the scene of the strike, trying to determine if al-Zawahiri was killed.

Pakistan's information minister could not confirm al-Zawahiri was the target of a CIA strike, and both the
Pentagon and White House declined to comment Friday night.

A doctor in the area told The Associated Press that at least 17 people were killed in the attack, but other witnesses at the scene said the death toll was higher.

Just last week, the Arabic-language news network Al-Jazeera aired a videotape in which the al Qaeda operative called on President Bush to concede defeat in Iraq.

It was al-Zawahiri's fifth message released over the past year, including ones claiming responsibility for the July attacks on the transit system in London, England.

The U.S. government is offering up to $25 million for information leading to the capture of al-Zawahiri, an Egyptian doctor who is considered to be the intellectual and ideological driving force behind al Qaeda.

He has been associated with bin Laden since at least 1987, when they met in Pakistan. He also is believed to be bin Laden's personal physician.

In 1998, al-Zawahiri merged his own Islamic militant group, Egyptian Islamic Jihad, into bin Laden's organization.

Three months after the September 11, 2001, terror attacks, U.S. forces attacked al-Zawahiri's residence in Afghanistan, killing his wife and children.

In March 2004, Pakistani troops launched an assault in Waziristan province, where intelligence indicated al-Zawahiri was hiding, but he was not captured.