Severed heads found in Iraqi fruit box

Prime Minister Nuri al-Maliki, meanwhile, ordered the phased release of 2,500 prison detainees, in what he described as a gesture to "promote national reconciliation".

The first batch of 500 prisoners were to be freed on Wednesday, from a total of 28,700 detainees being held in Iraqi and US prisons across the country, as of April 30.

Two men were killed and seven wounded as insurgents fired three mortars, which crashed near the interior ministry building, security officials and medics said.

The first mortar fell close to a hospital but without causing casualties, an interior ministry official said. "The other two fell in an industrial area close to the ministry and killed the two men and wounded seven others."

An Iraqi woman was killed in an explosion at central Baghdad's Al-Alawi bus and taxi station, the official said. A man was also wounded in the attack.

Three people, including a policeman and a woman, were shot dead in separate incidents in and around the restive town of Baquba, northeast of the capital, police said.

Meanwhile, a British military patrol early Tuesday escaped an apparent attack in Salekh, outside Basra, the main city in southern Iraq, a military spokesman said.

"Some sort of explosion went off near one of our patrol vehicles at 4 am (0000 GMT) today, but there were no casualties among coalition forces," Major Sebastian Muntz said.