A suicide bomber rammed his car into a bus carrying employees of Iraq's oil ministry as it passed a police academy, killing at least 10 people and wounding 30.
Local residents view the damage following a suicide bomb attack on a market in the Iraq town of Hilla, 100 km south of Baghdad today
The attack came as violence between Iraq's three main communities spikes ahead of an October 15th referendum on a controversial new constitution.
The bus was carrying employees of a state oil exploration company. Oil is the main revenue earner for Iraq's battered economy, and energy infrastructure and staff are frequently attacked by insurgents.
It was not immediately clear whether the bomber was targeting police or the oil ministry. Police were not able to say how many of the dead and wounded were police and how many were from the ministry.
Oil Minister Ibrahim Bahr al-Uloum told reporters he believed the bomber had aimed the attack at his staff. "Unfortunately these terrorist operations continue to target innocents," he said.
Violence has been escalating across the country ahead of the vote on a constitution for post-Saddam Hussein Iraq.
Iraq's US-backed government, dominated by Shi'ite Muslims and Kurds, is facing an insurgency by minority Sunni Arabs, who dominated Iraq for decades under Saddam but have been sidelined since his overthrow.
Sunnis, who make up about 20 per cent of the population, fear that if the charter is approved it will marginalize them even further by granting broad autonomy to Shi'ites in line with that already enjoyed by Kurds, including control of oil revenues.
Many have vowed to ensure the constitution is rejected. A campaign of ethnic and sectarian killings has led to fears Iraq's fragmented communities are sliding toward civil war.
US and Iraqi forces say militant insurgents are concentrated in the west of the country.