CBS News Correspondent David Martin reports U.S. intelligence has picked up signs of an Al Qaeda plot against American diplomatic posts in the Middle East and other Muslim countries--and that's the reason why some U.S. embassies and consulates will be closed Sunday.

According to Martin the intelligence does not mention a specific location.

Officials tell Martin this appears to be a real plot in the making and not just the normal chatter among terrorists talking about attacks they'd like to carry out.