BAGHDAD - Five car bombs killed at least 28 people in mostly Shi'ite Muslim neighbourhoods in Baghdad on Saturday, police and medics said.

The first explosion, a suicide car bombing, killed nine people at a police checkpoint in the Abu Dsheer district in the south of the capital, the sources said.

Four other car bombs killed a total of 19 people: one in the Bayaa district in southwestern Baghdad, one in the western district of Jihad and two in northern Baghdad's Kadhimiya, which boasts a major Shi'ite shrine.

The army and allied Shi'ite militia are trying to push back Sunni insurgents who swept through northern Iraq last month to within 70 km of Baghdad.