U.S. officials in Iraq say two American civilians have been killed and a third wounded in a roadside bomb blast south of Baghdad.

The U.S. Embassy says the victims, who worked for a private security firm protecting U.S. diplomats, came under attack Saturday on the main road to Hilla.

Meanwhile, there are reports that talks among Iraq's leading parties on forming a new government are stalled. Sources close to the talks say leaders of the Kurdish alliance's two factions were still debating Sunday a draft deal reached last week with the Shi'ite-dominated United Iraqi Alliance.

The two camps are supposed to announce an agreement on a new government Monday - two days before the Iraqi National Assembly convenes for the first time since January elections.

Some information for this report provided by AFP and AP.