US security contractor Blackwater was involved in at least 195 shooting incidents in Iraq since 2005, said a congressional report that also panned the State Department's oversight of the company.

State Department contractor Blackwater, under investigation for the shooting deaths of 11 Iraqis on Sept 16, will answer questions about that incident and others at what is expected to be a testy congressional hearing on Tuesday.

Senior State Department officials will also be grilled by the House of Representatives Committee on Oversight and Government Reform examining whether the growing use of military contractors undermines US efforts in Iraq.

In another development, the FBI said it had been asked by the State Department to send a team of investigators to Iraq to look into the Sept 16 shootings. No criminal charges have been filed yet against Blackwater over that incident.

A report prepared by the staff of committee chair Rep. Henry Waxman, released details from Blackwater's own reports of multiple incidents involving Iraqi casualties and said in most instances Blackwater fired first.

The memorandum also slammed the State Department's oversight of Blackwater and said it was often more interested in getting the company to pay off victims' families and 'put the matter behind us' than in investigating what happened.

It listed 195 shooting incidents from the start of 2005 until Sept 12 of this year, an average of 1.4 per week. Of those, there were 16 Iraqi casualties and 162 cases with property damage, the California Democrat said. He did not specify if there were fatalities.

'In 32 of those incidents, Blackwater were returning fire after an attack while on 163 occasions (84 percent of the shooting incidents), Blackwater personnel were the first to fire,' Waxman, a vocal critic of the Iraq war, said.

State Department rules say Blackwater's actions should be defensive rather than offensive.

Blackwater, which has been paid a little over $1 billion  by the US government since 2001, declined comment.

'We look forward to setting the record straight on this and other issues' when Erik Prince, Blackwater's chief, testifies before the committee, spokeswoman Anne Tyrrell said.

The report said Blackwater had fired 122 of its staff in Iraq over the past three years for a number of infractions, including 28 weapons-related incidents and 25 cases involving drugs and alcohol violations.

Waxman criticised the State Department's handling of several incidents involving Blackwater.

'It appears that the State Department's primary response was to ask Blackwater to make monetary payments to put the 'matter behind us' rather than to insist upon accountability or to investigate Blackwater personnel for potential criminal liability,' said the memorandum.

State Department spokesman Tom Casey declined to comment on specifics listed by Waxman but said the department was 'scrupulous' in its oversight of all contractors.

'These are tough jobs and these people often perform heroically in very difficult circumstances,' Casey said. 'But at the same time they have to be held accountable for their actions.'

In a shooting incident on Dec 24, 2006, a security guard for Iraqi Vice-President Adel Abdul-Mahdi was killed by an allegedly drunken Blackwater contractor, who was then flown out of the country and faced no charges, the memorandum said.

E-mail traffic from the US Embassy in Baghdad back to Washington described Iraq concerns over the incident.

'Iraqis would not understand how a foreigner could kill an Iraqi and return a free man to his own country,' it said.

The State Department's charge d'affaires recommended Blackwater pay $250,000 and give an 'apology.' Waxman noted the State Department's diplomatic security said that was too much and would cause Iraqis to 'try to get killed.' Eventually Blackwater agreed<