The top U.S. commander in Iraq, armed with a long-awaited report on the current situation there, told a deeply divided Congress Monday that troop levels could be reduced by next summer as military objectives were being met.

Gen. David Petraeus said the military objectives of the troop surge -- about 30,000 troops were deployed to Iraq over the past year -- were "in large measure" being fulfilled.

"I believe we will be able to reduce our forces to pre-surge level by next summer without jeopardizing the security gains," said Petraeus.

The additional 30,000 troops pushed the number of American soldiers in Iraq to a record-breaking 168,000.

"I also believe that it is possible to achieve our objectives in Iraq overtime, although doing so will be neither quick, nor easy," said Petraeus.

He said the report, which some have accused as being dictated by the White House, was written without any external pressures and had not been "cleared by nor shared with anyone in the Pentagon, the White House or the Congress.''

Alongside Washington's ambassador to Baghdad, Ryan Crocker, Petraeus listened earlier to attacks from Democrats and heckles from protesters.

Rep. Ike Skelton, D-Mo., chairman of the House Armed Services Committee, was cordial to Petraeus but shifted quickly into attack mode.

Petraeus is "almost certainly the right man for the job in Iraq, but he's the right person three years too late and 250,000 troops short," he said.

Skelton called on the men to "tell us why we should continue sending our young men and women to fight and die if the Iraqis won't make the tough sacrifices leading to reconciliation.

"....Are we merely beating a dead horse?"

Meanwhile, Tom Lantos, D-Calif., chairman of the House Foreign Affairs Committee, accused Petraeus and Crocker of serving the agenda of the Bush administration.

"The fact remains gentlemen that the administration has sent you here today to convince the members of these two committees and the Congress that victory is at hand," said Lantos. "With all due respect to you, I must say, I don't buy it."

Petraeus admitted military gains have been inconsistent since the troop surge was ordered last winter. However, he said overall violence has declined in Iraq in the past eight to 12 weeks. During the past two weeks, he said, the level of violence has hit a record low since June, 2006.

Iraq's military is also taking on more responsibility for security, he said. He used Anbar as an example, saying Iraqis in that province are turning against terrorists, and "we are seeing similar actions in other locations as well."

Recent polls cited by The Associated Press suggest 60 per cent of those surveyed would like to see a date set for withdrawing the troops.

About 35 per cent favoured keeping the troops in Iraq until the situation improves.

The testimony is expected to take several days, right through to the sixth anniversary of the Sept. 11 terrorist attacks on the United States.