In Baghdad, al-Maliki proposed a limited amnesty to help end the Sunni Arab insurgency as part of a forthcoming national reconciliation plan. The plan is likely to include pardons for those who had attacked only U.S. troops, a top adviser said.

Al-Maliki's declaration of openness to talks with some members of Sunni armed factions, and the prospect of pardons, are concessions that previous, interim governments had avoided.

Also yesterday, al-Maliki's government deployed thousands of soldiers and police to patrol Baghdad and man checkpoints in the first major security initiative of his month-old administration, aimed at combating the killings and kidnappings that have become near-daily events. The actions caused huge traffic jams.

Violence in the city continued, with at least 11 people killed.

Bush called reporters to the White House on short notice in an apparent effort to stoke the positive momentum generated by last week's killing of Abu Musab al-Zarqawi, the leader of the insurgent group al-Qaeda in Iraq and because of al-Maliki's success in completing a coalition government in Baghdad.

With pressure from Democrats building in Congress to establish a timetable for withdrawing the 132,000 U.S. troops in Iraq, Bush seemed eager to plunge into a developing election-year debate, saying, “I will remind the American people if we pull out before we achieve our objective, the world will be a lot more dangerous and America will be more at risk.”

He said, “One message that I will continue to send to the enemy is: Don't count on us leaving before the mission is complete. Don't bet on American politics forcing my hand because it's not going to happen. I'm going to make decisions not based upon politics, but based upon what's best for the United States of America.”

Admitting to jet lag after flying more than 20 hours to and from Iraq in order to spend five hours in Baghdad's Green Zone, Bush said he endured the ordeal to satisfy himself that Iraq now has the leadership it needs.

Bush said, “One of the reasons I went to Iraq was to be able to sit down with an Iraqi government to determine whether or not they have the will to succeed.”

He added, “I've eliminated that uncertainty.”

With Bush's flight shrouded in extraordinary secrecy, al-Maliki was informed about his guest's arrival only minutes before they actually met.

Asked whether giving such short notice might have sent a negative signal to the new government, Bush said he was “a high-value target . . . and Iraq's a dangerous place. And the American people got to know that I will take precautions when I travel somewhere. I'm not going to put our government at risk.”

Bush was asked about what he thought about a possible amnesty for Iraqi insurgents. While avoiding specifics, Bush said he thought it was good for al-Maliki to work for reconciliation.

“If you're a person stuck in the past, you tend to be bitter and look for ways to seek revenge. I didn't sense that. I did have a strong sense that they're really happy to get rid of Saddam Hussein, to a person. They believe he wrecked their country in more ways than one,” Bush said.

He added, “But I didn't have that great sense of people being so bound up in bitterness that they weren't willing to think positively about the future. And I think that's important.”

Bush visited Iraq with what he said were twin messages for al-Maliki: The United States would not abandon Iraq, but Iraq needed to do more to tackle its problems.

In Baghdad, the Operation Forward Together security crackdown involves 75,000 Iraqi army and police forces backed by U.S. troops.

The operation includes a curfew extended by 4½ hours – from 8.30 p.m. until dawn – and a weapons ban.

As a result of the expanded checkpoints, there were traffic-snarling jams across Baghdad.

“We have noticed less and less people shopping, but I would rather have security than more customers,” said Wisam Saad, 29, who stood in a shop empty of customers, surrounded by cigar boxes, teapots and trinkets.

But the heightened police presence did not stop all violence. In the Adhamiya area north of Baghdad, gunmen clashed with Iraqi army soldiers manning a checkpoint, according to Capt. Riyad Ali of the Baghdad police.

The fight lasted about an hour and five attackers and two soldiers died, he said.

A car bomb targeting a police patrol in the Qahira neighborhood of eastern Baghdad killed four people and injured eight others, said Maj. Saad Mahmoud of the Ministry of Interior Operations room.

Iraq's previous, transitional government, led by Ibrahim al-Jaafari, a Shiite, launched a similar crackdown last year but it failed to deter the violence. After elections in December selected Iraq's first full-term parliament since the fall of Hussein, al-Maliki, also a Shiite, won appointment as prime minister.

His month-old administration has seen rapid movement on some long-standing demands from Sunni opponents of the Shiite governments, such as the U.S.-Iraqi agreement to free thousands of detainees in U.S.-run prisons in Iraq this month. Hundreds are due to be released from the Abu Ghraib prison today.

The Arab League yesterday postponed a reconciliation conference for Iraq that had been set for next week until August.

Adnan Ali al-Kadhimi, a top adviser to al-Maliki, said the conference was delayed in part so Iraq could decide who might be eligible for any amnesty. It was not clear how the government would verify which insurgents have been responsible for which types of attacks.

“The government has in mind somehow to do reconciliation, and one way to do it is to offer an amnesty, but not a sort of unconditional amnesty,” al-Kadhimi said in a telephone interview. “We can see if somehow those who are so-called resistance can be accepted if they have not been involved in any kind of criminal behavior, such as killing innocent people or damaging infrastructure – and even infrastructure, if it is minor, will be pardoned.”

Asked about clemency for those who attacked U.S. troops, he said: “There's some sort of preliminary understanding between us and the MNF-I,” the U.S.-led Multi-National Force-Iraq, “that there is a patriotic feeling among the Iraqi youth and the belief that those attacks are legitimate acts of resistance and defending their homeland. These people will be pardoned definitely, I believe.”

Asked about pardons for those who had attacked Iraqi forces, he said: “This needs to be carefully studied or designed so maybe the family of those individuals killed have a right to make a claim at the court, because that is a public right. Or maybe the government can compensate them.”