A double car bombing in a mainly Shia district of the Iraqi capital, Baghdad, has killed at least 60 people and injured more than 130.

The two blasts tore through a busy open-air market in the New Baghdad area in quick succession, witnesses said.

Many of the injured were carried to hospital on makeshift stretchers. A badly-burnt Red Crescent ambulance could be seen at the scene of the explosions.

Large plumes of smoke rose above the city, which was rocked by a third car bomb at a police checkpoint in the Sadr City district shortly afterwards. Two people were killed.

The attacks are the deadliest since a joint US-Iraqi security offensive was launched on Wednesday.

They came a day after US Secretary of State Condoleezza Rice visited Baghdad and said the security operation had begun well.