BAQUBA, August 19, 2008 (AFP) - The government ordered a probe into an Iraqi military unit's raid Tuesday on the governor's office in Diyala province during which officials said two people were killed and police came under fire.

Prime Minister Nuri al-Maliki ordered the formation of a committee to find out how Iraqi forces came to fight each other in Baquba, the capital of Diyala, said defence ministry spokesman Mohammed al-Askari.

The governor's secretary and a guard were killed during the raid, while four other guards were wounded, Askari said.

'This committee, made up of the commander of forces involved on the ground and special judges, must determine the reasons for this incident and the lack of coordination between the command in Baghdad and Iraqi forces' in Baquba.

The pre-dawn incident in Baquba sparked clashes between soldiers sent from the capital and local security forces, said the restive province's governor Raad Rasheed Mulla Jawad.

'During the night, Iraqi forces from Baghdad burst into the provincial council building,' arriving in Humvee armoured vehicles, said Jawad, whose province northeast of the capital remains one of Iraq's most dangerous areas.

'They were hitting everyone. They disarmed the guards and killed my secretary, Abbas al-Tamimi,' he said, adding that the soldiers also arrested Hussein al-Zubaidi, head of the provincial council's security committee.

'They took cars, mobile phones, money and then left,' Jawad said, adding that an investigation had been launched to identify the culprits.

Fighting then broke out at the headquarters of the provincial council between soldiers and Iraqi security forces. Jawad said the soldiers also raided the home of Baquba university's rector who was likewise arrested.

The defence ministry's spokesman did not explain the aims of the operation, or specify if those killed or arrested were actually targets of the special unit.

Another defence ministry official told AFP, on condition of anonymity, that the unit involved was a part of Iraqi special forces which took orders only from the US-led coalition.

But the US military, which has a base in Baquba, denied involvement.

'The Iraqi unit involved in the operation at the Diyala Governance Centre last night was not under the command of coalition forces,' said a US military spokesman, Major John Hall.

'This was an Iraqi planned and executed operation without the involvement of the coalition forces ... An (American) air weapons team was in the vicinity of the incident but did not engage any targets.'

All 41 members of the provincial council suspended work in protest at the incident, said Abrahim Bajilan, the council's chief. The Iraqi Islamic Party, of which the arrested Zubaidi is a member, withdrew its seven councillors.

Last month, with support from US forces, 50,000 Iraqi soldiers and police launched a major crackdown against Al-Qaeda fighters and other insurgents in Diyala province.