The killing of an American who directed al-Qaida's media campaign from his Pakistani hideout is likely to be a big blow for the militants, especially as they wage a propaganda war with the Islamic State group.

American al-Qaida member Adam Gadahn, who faced treason charges in the United States, was killed early this year in a strike on an al-Qaida camp in Pakistan, near the Afghan border, U.S. officials said Thursday.

"He was highly important. He was the man on their media front line," said Ahmed Rashid, a Pakistani author and expert on the Taliban and al-Qaida.