Iraqi police and soldiers immediately cordoned off the area, which was covered with pieces of flesh, pools of blood and shreds of clothing.
Captain Muthana Khalid Ali said the attack happened at 9.15 a.m. in Hillah, about 60 miles south of Baghdad, when two suicide bombers wearing explosive belts blew themselves up in the middle of a group of policemen.
Dr Ayad Jabr, of Hillah Hospital, said ambulances have brought the bodies of 10 slain policemen to his hospital. Another 25 wounded policemen were brought to the hospital for treatment.
About 500 policemen had gathered outside the local mayor's office to protest a government decision to disband their special forces unit.
Ali alleged some policemen had presented fake documents to the Hillah mayor's office several months ago approving the opening of a special forces unit in this city.
But the new government, announced April 28, discovered the documents were not legitimate and decided to close the special forces station, Ali added. Interior Ministry officials were not immediately available for comment.
The attack came as US troops detained the head of Iraq's largest Sunni Muslim political party during a house raid early Monday in western Baghdad, a top party official and police said.
Mohsen Abdul Hamid, head of the Iraqi Islamic Party, was detained by American soldiers along with his three sons and four guards, said party-secretary-general Ayad al-Samarei. US military officials could not immediately confirm the detentions.
Al-Samarei said American soldiers raided Hamid's home at around 6 a.m. and confiscated various items, including a computer.
"This is a provocative and foolish act and this is part of the pressure exerted on the party," he said.
"At the time when the Americans say they are keen on real Sunni participation, they are now arresting the head of the only Sunni party that calls for a peaceful solution and have participated in the political process," he added.
In a statement, the party demanded Hamid's immediate release, saying he "represents a large sector of the Iraqi people."
"This irresponsible behavior will only complicate the situation," the party statement said.
Sunni Muslims were Iraq's dominant community under Saddam Hussein, but they have lost their influence since the dictator's ouster two years ago and the country's predominant Shia community gained political power.
The country's raging insurgency is believed to be driven mainly from disaffected Iraqi Sunnis and extremist Islamists from neighboring, predominantly Sunni Arab states.
Tensions have been high in recent weeks during a spate of violence, some which has demonstrated Sunni-Shia tensions. Sunni and Shia religious leaders have been trading accusations against each other's communities amid the killings of hundreds of people, including Shia and Sunni clerics.
Hamid, aged in his late 60s, is regarded as a moderate Islamic leader. He was a member of the now dissolved US-appointed Iraqi Governing Council and and has been involved with the party since the 1970s and headed it since 2003.
