SANAA, Yemen (AP) - A security official who worked for the U.S. Embassy in Yemen has been assassinated in a drive-by shooting in the Yemeni capital.

Yemeni security officials say the victim had worked for the U.S. Embassy for nearly 20 years, most recently as a lead investigator into last month's assault on the compound by Yemenis protesting the film that mocked the Prophet Muhammad. He was on his way to work today when a gunman on a motorcycle opened fire at him and fled.

Officials say the attack bore the hallmarks of al-Qaida. It resembled a series of other recent assaults by Al-Qaida's Yemen branch targeting Yemeni intelligence, military and security officials.

An elite team of about 50 Marines was sent to Yemen to bolster security at the U.S. Embassy after the Sept. 13 attack. Officials say the Marines were scheduled to leave today. It's not clear if the attack would affect those plans.

The officials spoke on condition of anonymity because they were not authorized to speak to the media.

Copyright 2013 Associated Press. All rights reserved. This material may not be published, broadcast, rewritten, or redistributed.