Five Iraqi teachers were abducted in front of their pupils and executed at a primary school south of Baghdad today.

The shooting happened as teachers and students were leaving the building at the end of the school day in Muelha, a village near the town of Iskandariyah. Contrary to earlier reports that children had been forced to watch the murders, no-one else was in the classroom at the time of the shooting, said police Captain Muthana Khaled.

The five male teachers were kidnapped as they were leaving the school in a minibus, along with their driver, Khalied said. All six men were then taken back into the classroom, lined up against a wall and shot to death by the gunmen, he said.

Muelha, about 50 km (30 miles) south of Baghdad, is located in a predominantly Sunni area of Iraq, but the identities of the people killed were not immediately known.

Iraq’s Sunni-led insurgency against US forces in Iraq sometimes causes revenge killings by the country’s majority Shia population.

Earlier today at least 10 Iraqis died in a suicide bomb attack on a police checkpoint guarding Iraq’s oil ministry, irrigation ministry and national police academy in the capital Baghdad. The explosion also devastated a nearby private bus carrying 24 oil ministry employees to work, said police Captain Nabil Abdel Qadir.

The blast killed at least seven policemen and three people on the bus, Captain Qadir said. It wounded 36 Iraqis, 14 of them policemen and 22 of them passengers, he said.

"The insurgents are targeting Iraqi government employees," said the country's Oil minister, who visited the scene of the bombing. "These savage acts won’t undermine the forthcoming people’s referendum on the new Iraqi constitution."

Elsewhere in Iraq three American soldiers were killed in two separate attacks by insurgents using roadside bombs. Two of the soldiers died in western Baghdad. The third was working with the 42nd Brigade when he was killed about 50 miles southeast of the capital.

The deaths raised to 1,917 the number of US service members who have died since the beginning of the Iraq war in March 2003.

The deaths came as US and Iraqi officials tried to pacify Iraqi citizens with a goodwill gesture by freeing 500 detainees from Abu Ghraib prison ahead of the Muslim holy month of Ramadan.

After a brief ceremony at Abu Ghraib prison on the outskirts of Baghdad, about 500 detainees left on public buses. They were the first of 1,000 due to be freed before Ramadan begins next week, the US military said. Another 1,000 were released from the prison last month. The military said the freed prisoners were not guilty of serious, violent crimes such as bombing, torture, kidnapping, or murder.

Arab governments often pardon non-violent offenders during Ramadan, which this year is expected to begin on October 4 or 5. But it was the first time US and Iraqi officials had made such Ramadan releases at Abu Ghraib.

The concession appeared to be part of a government effort to persuade citizens to vote in the October 15 national referendum on Iraq’s draft constitution, particularly the Sunni minority.

Approving the constitution would be an important step in the country’s transformation into a democracy. But many Sunni leaders and insurgents are calling for a boycott or a "no" vote in the referendum. They say the document would leave minority Sunnis with far less power than the country’s Kurds and majority Shia Muslims.

If two-thirds of voters in any three of Iraq’s 18 provinces reject the charter, a new government must be formed and the process of writing a constitution must start all over again.

Abu Ghraib prison was built by Saddam Hussein’s regime in the 1970s, and after his overthrow in 2003 was retained as a prison by the US occupation authorities. It gained international notoriety after a US military personnel were charged with humiliating and assaulting detainees at the facility.

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