Bush, who will address the UN General Assembly in New York on Tuesday, said he liked UN chief Kofi Annan personally but warned that that many Americans were wary of the United Nations and that he agreed when it came to Sudan.

"I'm frustrated with the United Nations in regards to Darfur," the US president said in a wide-ranging 58-minute press conference in the White House Rose Garden. "The United Nations hasn't acted."

The UN Security Council last month approved the deployment of a 20,000 UN force in Darfur to replace an African Union force, whose mandate runs out on September 30. But the Sudanese government has refused to give its blessing.

"I'd like to see more robust United Nations action. What you'll hear is, 'Well, the government of Sudan must invite the United Nations in for us to act.' Well, there are other alternatives, like passing a resolution saying, 'We're coming in with a UN force in order to save lives,'" he suggested.

Amid European optimism that talks with Iran are making progress towards defusing the standoff over its nuclear weapons, Bush warned US partners not to take pressure off Tehran, which he suggested was playing for time.

"My concern is that, you know, they'll stall; they'll try to wait us out," he said. "So part of my objective in New York is to remind people that's stalling shouldn't be allowed."

Asked whether he would consider meeting with Iranian President Mahmoud Ahmadinejad on the UN sidelines, Bush replied sternly: "No, I'm not going to meet with him."

"I have made it clear to the Iranian regime that we will sit down with the Iranians once they verifiably suspend their enrichment program, and I meant what I said," the US president said.

Bush denied that there was now a civil war in Iraq, where nearly 2,700 US troops have been killed and many more wounded, and rejected a US intelligence report of a dire picture of al-Anbar province.

US generals and Iraqi leaders "just don't agree with the hypothesis it is a civil war," he said, adding that "this business about 'al-Anbar is lost' is just not the case. That's not what our commanders think."

That was a direct response to a recent US Marines intelligence assessment that reportedly declared prospects for securing Anbar "dim" and warned "there is almost nothing the US military can do" to improve the situation.

The president's comments came with less than two months before November 7 legislative elections, at a time when many of his Republicans fear the unpopular war in Iraq could cost them dearly at the polls.

Bush used his opening statement to mount a forceful defense of some controversial strategies in the global war on terrorism, including warrantless wiretapping of Americans, secret CIA prisons, military tribunals for terrorism suspects, and harsh interrogation tactics some call torture.

Bush warned the US Congress that "time is running out" for lawmakers to pass legislation safeguarding such practices, which he called vital to saving US lives and preventing attacks like the September 11, 2001 strikes.

He grew visibly annoyed when asked whether former US secretary of state Colin Powell was right to warn that "the world is beginning to doubt the moral basis of our fight against terrorism."

"It's unacceptable to think that there's any kind of comparison between the behavior of the United States of America and the action of Islamic extremists who kill innocent women and children," said Bush.

On another front, he rejected charges that his administration has not done enough to catch Al-Qaeda mastermind Osama bin Laden as an "urban myth" fueled by political ambitions.

"We have been on the hunt, and we'll stay on the hunt until we bring him to justice," said Bush.

But he acknowledged telling a conservative journalist earlier this week that he would not send "thousands of troops" into the remote region of the Pakistan border with Afghanistan, where bin Laden is thought to be hiding.

"If he is in Pakistan," said Bush, "Pakistan's a sovereign nation. In order for us to send thousands of troops into a sovereign nation, we've got to be invited by the government of Pakistan."

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