Policemen who took part in the retaliatory shootings ofscores of men in northwest Iraqthis week, have been released a day after being arrested to preventunrest, the provincial governor says.

Meanwhile, bombings and shootings on Thursday killed atleast 12 people in other parts of Iraq, security officials said.

Also on Thursday, Ryan Crocker, a USdiplomat, was sworn in as the new USambassador to Iraq.He pledged to stand by Nuri al-Maliki, Iraq's prime minister, and saidparliament must push ahead with reconciliation efforts.

Crocker replaces Zalmay Khalilzad, who left the country thisweek.

At his swearing-in ceremony at the US embassy in Baghdad's Green Zone, Crocker said:"This government, under the leadership of Prime Minister Maliki, mustcontinue to take the necessary steps to unify this country, and to delivertangible improvements to the lives of all Iraqis."

Daily violence

Crocker's remarks came against a backdrop of continuedviolence in many parts of Iraq.

Five people were killed and nearly 20 others wounded inThursday's biggest attack, when a car bomb exploded in the town of Mahmudiya, 30km south of Baghdad, police said.

In the capital, two policemen died when a car rigged withexplosives and stuffed with a corpse blew up when they came to retrieve thebody, a security official said.

Iraqi policemen found the car parked in al-Amel district ofcentral Baghdadwith a corpse inside.

When the policemen approached to examine the body, thevehicle exploded, killing two of them and wounding another six, the securityofficial said.

Another two policemen were killed and two more wounded whenarmed men opened fire on the convoy of the chief of traffic police as it passedthrough a district of northern Baghdadnear the Sunni al-Nida mosque, an official said.

Three more Iraqis were killed and another 20 wounded in aroadside bomb explosion in Baghdad'ssouthwestern Baya district.

Sectarian tension

In Tal Afar on Thursday, the governor of Nineveh province acknowledgeda setback to the authorities' efforts to deal with thesurge in sectarian strife.

Hours after truck bombs killed 85 people in a Shia area ofTal Afar on Tuesday, up to 70 Sunni men were shot dead in a town which only ayear ago was held up by George Bush, the US president, as an example ofprogress towards peace.

Durad Kashmula, the governor of Ninevehprovince, said on Thursday at a news conference in Mosul: "Yes, there are policemen who areinvolved.

"They have been arrestedbut released afterwards due to demonstrations and to deter strife," hesaid, referring to protests in Tal Afar on Wednesday.

However, Kashmula said they would be brought to justice indue course.

Brigadier Najim al-Jubouri, mayor of Tal Afar, which isclose to the Syrian border and the regional capital Mosul, said on Wednesdaythat 18 people had been detained over the shootings. It was not clear how manyremained in custody on Thursday.

Salih Qadu, head doctor of Tal Afar hospital, said the finaltoll from the two bombs on Tuesday was 85. He said 60 bodies of men shot in theaftermath had been brought to the hospital. A senior Iraqi army officer put thetoll from those attacks at 70.

Kashmula said "hidden hands" were trying to stirup sectarian strife in Tal Afar, but he vowed to restore normalcy to the town,which has seen growing tension between Shias, Sunni Arabs and Turkish-speakingTurkmen.

Putin's message

At the international level, Vladimir Putin, the Russian president, onThursday called for a deadline on the presence of foreign troops in Iraq in orderto avert civil war.

Consultations with political and religious leaders were required, aswell as "clear time limits for the foreign military presence in thecountry", Putin said in a statement sent to the Arab League summit in Riyadh.

The US senate could voteon Thursday on a war funding bill that includes a binding provision towithdraw US troops from war-torn Iraq, where more than 3,235American soldiers have died, by March 31, 2008.

Bush reiterated on Wednesday his pledge to veto the legislationif it crosses his desk, but Democrats are pressing the president to sitdown with legislators to find common ground.

Nancy Pelosi, the speaker of the House of Representatives, said: "Letus sit down together to do what is right for the American people, toaddress the war in Iraq, so that we can bring it to an end and bring ourtroops home safely and soon."