Acknowledging that United States will take time to win the war in Iraq, President George W Bush has said that there is evidence that Iran is responsible for the surge in attacks against American troops in that country.

While there is 'incontrovertible evidence' that Teheran's Quds force inside Iraq is responsible for violence against Americans, Bush said he cannot say for sure if Iranian President Mahmoud Ahmajinejad gave the direct orders.

At an hour long press conference, his first this year, in the East Room of the White House on Wednesday, Bush said: "The operation to secure Baghdad is going to take time, and there will be violence."

As the House of Representatives started a debate on Wednesday on a non-binding resolution on Iraq, Bush reminded lawmakers that while he understands where many of them are coming from, Capitol Hill cannot refuse funds needed to win the Iraq war.

The Democrat-controlled House debated the measure of sending an additional 21,500 troops with most lawmakers, including some Republicans, opposed to the surge plan.

"They have every right to express their opposition and it is a non-binding resolution. American troops are counting on their elected leaders in Washington DC, to provide them with the support they need to do their mission," Bush said.

The President was pointedly asked if he could retaliate against Iran without risking a war.

"What we do know is that the Quds Force was instrumental in providing these deadly IEDs to networks inside of Iraq... What we don't know is whether or not the head leaders of Iran ordered the Quds Force to do what they did," he said.

"If we find agents who are moving these devices into Iraq, we will deal with them. I have put out the command to our troops... our commanders, that we'll protect the soldiers of the United States and innocent people in Iraq, and we will continue doing so," Bush said.

"I was confident that the Quds Force, a part of the Iranian government, was providing weaponry into Iraq. And to say it is 'provoking Iran' is just a wrong way to characterise the commander-in-chief's decision to do what is necessary to protect our soldiers in harm's way," he said.      

The President said, "There are weapons in Iraq that are harming US troops but whether Ahmadinejad ordered the Quds Force to do this, I don't think we know. But we do know that they are there. And I intend to do something about it."

"Later this week, the House of Representatives will vote on a resolution that opposes our new plan in Iraq before it has a chance to work. They have every right to express their opinion, and it is a nonbinding resolution," he added.

"Soon, Congress is going to be able to vote on a peace of legislation that is binding, a bill providing emergency funding for our troops," Bush said in a clear reference to where his specific interest was.      

"I am going to make it very clear to the members of Congress starting now that, you know, and they need to fund our troops and they need to make sure we have the flexibility necessary to get the job done," the President added.

"My job is to protect our troops... Now does this mean you are trying to have a pretext for war? No. It means I am trying to protect our troops," he maintained.

Defending his troops surge plan and asserting that it is important to help the US-led forces in Iraq, Bush said, "If you think the violence is bad now, imagine what it will look like if we don't help them secure the city, the capital city of Baghdad."

On the six-party talks in Beijing over North Korea's nuclear disarmament issue, the President said: "There is a lot of work to be done to make sure that the commitments made in this agreement become a reality."