A convoy of 19 vehicles carrying 14 civilians was hijacked Thursday near Nasiriyah. Four Americans are believed to have been amongst the hostages. The Pentagon has confirmed the hijacking.

The incident came after the official announcement on state-run television that the Iraqi police had issued a warrant for the arrest of Sunni leader, mullah Harith al-Dhari, who heads the Sunni Association of Muslim Scholars, a religious organization.

Meanwhile, Sunni gunmen attacked a bakery in Baghdad, killing nine people.

Friction between Sunnis and Shiites has escalated in the past few days in response to the accusation from Sunnis in the government that Shiite officials responsible for the security of civilians in Baghdad, are not cracking down on Shiite militia groups. Several Sunnis have threatened to leave the government over distrust of Shiite colleagues.

The issue of the warrant for al-Dhari may further stoke the fire.