BAGHDAD: A spate of bombings in Baghdad on Thursday killed at least seven people and wounded dozens more, with the deadliest violence to hit the capital in weeks breaking a relative calm.

Roadside bombs and explosives-packed cars detonated across a half-dozen neighbourhoods in the north, south and west of Baghdad, underlining persistent security concerns even as international energy companies met in the centre of the capital to bid on oil and gas exploration blocks.

Thursday's deadliest attack took place in the north Baghdad neighbourhood of Shuala, where a car bomb killed at least four people and wounded 14 others, an interior ministry official and a medic said.

Separate bombings also struck Al-Amriyah, Ghazaliyah and Yarmuk in west Baghdad, and Dora and Saidiyah in the south of the capital, all Thursday morning.

A series of roadside bombs in Al-Amriyah, west Baghdad, killed two people and wounded at least seven, officials said, while a car bomb near the home of an official in Prime Minister Nuri al-Maliki's office killed one passerby.

The latter attack in Yarmuk, also in the capital's west, left the official unharmed.

An interior ministry official, speaking on condition of anonymity, put the overall toll at seven killed and 37 wounded, while medical sources said nine people were killed and 27 wounded.

Differing tolls are common in the chaotic aftermath of attacks in Iraq.

Thursday's violence was the worst to hit Baghdad since April 19, when attacks in and around the capital killed 17 and wounded 106.

Violence in Iraq has declined dramatically since its peak in 2006 and 2007, but attacks remain common, especially in Baghdad. A total of 126 Iraqis were killed in violence in April, according to official figures.