Two hotels in Baghdad used by foreigners and Iraqi officials have been hit by rockets.
Outside the Baghdad Hotel, guards said there were at least three casualties. The Ishtar Sheraton Hotel was also hit, but staff said nobody in the hotel had been wounded.
Nearby, police found a pickup truck flipped over on its side with 17 rocket launchers and a crude firing mechanism inside.
An Iraqi child looks at the rocket tubes set in the back of a bus that were used for an attack on the Sheraton hotel
Police said they believed three rockets had been fired and the force of launching them had flipped the truck over.
An empty bus was in flames outside a mosque opposite the Sheraton. Police said it had been boobytrapped but there were no casualties.
The bus was in Firdaws Square, where a statue of Saddam Hussein was symbolically toppled live on television when US troops took the city last April.
US and Iraqi security forces have been on high alert this week, fearing attacks in the wake of the formal handover of sovereignty to an Iraqi interim government that took place on Monday, two days earlier than planned.