All the talk about Iraq, weapons of mass destruction and malafide intentions finally got to Colin Powell.

The normally courteous US secretary of state lost his cool during his testimony on Iraq at a congressional hearing and shouted at a Congressman's staffer who nodded his head when he was talking about US-led war on Iraq.

He described the staffer's action as 'an editorial comment'. During the House International Relations Committee hearing, Powell noticed the staffer shaking his head as he repeated the Bush Administration's defence of Iraq war -- that even if Saddam Hussein did not have massive quantities of WMDS, he had the capacity to produce them and was an evil man.

"Are you shaking your head for something, young man, back there? Are you part of these proceedings?" he burst out.

Powell's scolding threatened to derail the hearing. Congressman Sherrod Brown, a 12-year veteran of the House, objected: "Mr Chairman, I've never heard a witness reprimand a staff person in the middle of a question."

Powell shot back: "I seldom come to a meeting where I am talking to a Congressman and I have people aligned behind you giving editorial comment by headshakes."

"Well, I think people have opinions," Brown retorted.

Congressman Dana Rohrabaher (Republican) rushed to defend Powell, saying, "I think the Secretry is owed an apology for that, not a reprimand."

That brought a reaction from Democratic Congressman Gary Ackerman, who had earlier in the day been cut off by Rohrabacher during a statement. "Mr Chairman, has the gentleman who is speaking been recognised?" he asked.

Chairman Henry Hyde (Republican) urged all members to calm down despite the 'very emotional subject'.

Powell, however, became testy when Brown said, in a reference to questions about whether Bush had completed his National Guard service: "You (Powell) are one of the very few people in this Administration that understands war. We have a president who may have been AWOL (Absent Without Leave from duty, a very serious charge in the military)."

"First of all, Mr Brown, I won't dignify your comments about the president because you don't know what you are talking about," Powell said.

"I am sorry, I don't know what you mean, Mr secretary," said Brown.

"You made a reference to the President," Powell pointed out.

"I say he may have been AWOL," Brown replied.

"Mr Brown, let's not go there. Let's not go there in this hearing. If you want to have a political fight on this matter, that is very controversial, and I think is being dealt with by the White House, fine. But let's not go there," Powell said.