Adam Gadahn, an American spokesman for al Qaeda, has been arrested in Pakistan, a senior Pakistani government official source told CNN.

The official said Gadahn was arrested Sunday in Karachi.

Several U.S. officials told CNN that they have no indication that Gadahn has been captured.

News of the arrest came hours after Islamist Web sites posted video of Gadahn praising a November shooting rampage at the U.S. Army base in Fort Hood, Texas. On the video, Gadahn said the Army major charged with gunning down 13 people "lit a path" for other Muslim service members to follow.