The lift area between the eighth and ninth floors of the Ishtar Sheraton Hotel was struck. Debris and shattered glass littered the hotel's lobby.
The hotel, where U.S. contractors and Western journalists stay, was also hit late on Wednesday, again without casualties.
"This is a regular day for us," said U.S. First Lieutenant Kurt Muniz, as he led several soldiers on a foot patrol in the area.
He said the attackers left behind leaflets urging workers at the Ishtar Sheraton to stop working at the hotel.
A neighbor said he saw a car speeding away from a nearby street immediately after the attack.
A U.S. military spokesman said three or four rockets struck in the vicinity of the U.S.-led Coalition Provisional Authority complex in the center of Baghdad on the western bank of the Tigris River.
Warning sirens sounded several times at the complex, which was once one of Saddam's palaces.
The all-clear was sounded some two hours after the attacks, which a military spokesman said were under investigation.
Three Policemen Wounded In Bomb Blast
December 25, AFP
A roadside bomb exploded on a busy Baghdad street on Thursday, blowing off the hand of a policeman and seriously wounding two other officers, fellow policemen said.
The policeman who lost his hand had approached the bomb, hidden in a black bag, on Palestine Street, a busy commercial boulevard in the city's centre.
It blew up just as he stepped forward, said Colonel Ahmed Hussein.
"He went toward the bomb. When he just moved his hand trying to do his job, it exploded," Mr Hussein said.
"Two other policemen were seriously hurt by shrapnel, one hit in the stomach and the other in leg."
The policeman's severed hand was lying in a plastic bag in a police pick-up truck.