NEW YORK, Aug 19: A top Republican congressman has broken ranks with his party asserting that he believes that the US military assault on Iraq was unjustified and that the situation there had deteriorated into "a dangerous, costly mess."

"I've reached the conclusion, retrospectively, now that the inadequate intelligence and faulty conclusions are being revealed, that all things being considered, it was a mistake to launch that military action," Representative. Doug Bereuter, of Nebraska said in a letter to constituents on Wednesday.

"Left unresolved for now is whether intelligence was intentionally misconstrued to justify military action," he said. The letter was reported by the Lincoln Journal Star in its Wednesday editions.

"From the beginning of the conflict, it was doubtful that we for long would be seen as liberators, but instead increasingly as an occupying force," he said. "Now we are immersed in a dangerous, costly mess, and there is no easy and quick way to end our responsibilities in Iraq without creating bigger future problems in the region and, in general, in the Muslim world."

Mr Bereuter is a senior member of the House International Relations Committee and vice chairman of the House Intelligence Committee. He is stepping down after 13 terms to become the president of the Asia Foundation, effective September 1.

Commenting on Mr Bereuter letter a Kerry Campaign spokesman, Bill Burton said: "Anytime a member of the president's party directly challenges the president - on any issue, especially war - it's notable".