Attackers fired a rocket (search) that struck the Sheraton Hotel housing foreign contractors and journalists early Wednesday. Security guards said there were no casualties.

The rocket slammed into a sixth-floor concrete ledge that forms the roof of a banquet room, said security guard Rabah Nasser. The lobby of the building, which has been attacked before, was strewn with glass.

Earlier, guards said the hotel had been struck by a rocket-propelled grenade (search).

Across the Tigris (search) river, sirens wailed briefly in the area housing the U.S.-led coalition headquarters.

A U.S. military spokesman said he had no information.

U.S. soldiers protect the Sheraton hotel and the neighboring Palestine hotel, both of which are ringed by concrete blast walls to ward off bombing attempts.