Iraq's interior ministry has launched a probe into allegations that death squads are operating within the police force and targeting Sunni Arabs.

A senior official, Major-General Hussein Kamal, said the probe follows the arrest of 22 people dressed as police commandos, who were taking away a Sunni man to be shot.

An American general, Major General Joseph Peterson, told a U.S. daily, The Chicago Tribune, that the men were stopped by an Iraqi checkpoint in northern Iraq last month.

Sunnis often complain of atrocities by Iraqi police, most of whom are Shi'ite Muslims.

Meanwhile, Iraqi insurgents killed at least nine people in a series of attacks in Baghdad and northern Iraq Thursday.

And radical Shi'ite cleric Moqtada al-Sadr arrived in Jordan today for talks with King Abdullah and other officials in coming days.

Some information for this report was provided by AFP and AP .