WASHINGTON -- Facing a surge in violence, President Bush said Tuesday the United States will change tactics and stiffen defenses in Iraq and will not be intimidated by a wave of suicide bombers intent on discouraging cooperation with the American occupation.

"We're constantly looking at the enemy and adjusting," Bush said. "Iraq is dangerous, and it's dangerous because terrorists want us to leave, and we're not leaving."

Twelve months before the presidential election, Bush made a broad defense of his foreign policy during a news conference, saying he will tell Americans during the upcoming campaign that "the world is more peaceful and more free under my leadership and America is more secure."

A day after bombings in Iraq killed three dozen people, Bush came to the Rose Garden on a chilly fall morning to announce the United States would set up more blockades and inspections and seek to give Iraqis a bigger role in intelligence-gathering to thwart attacks.

Bush's words appeared intended to address criticism -- particularly from Democratic presidential candidates -- that the White House had failed to anticipate rising violence in Iraq and was uncertain about how to deal with it and protect American lives.

Blaming the increase in bloodshed on foreign terrorists and Saddam Hussein loyalists, Bush said more troops would be deployed along Iraq's borders.

Iraq dominated the 48-minute news conference, although other topics were also covered.

Secretary of State Colin Powell reinforced Bush's words about new tactics. "In combat operations you make adjustments and you make changes as circumstances change. And that is what we are doing now."

Powell, in an interview with Radio Sawa, the U.S.-financed broadcast service to the Arab world, said, "Our military is adjusting and we are also adjusting by accelerating the development of an Iraqi police force and Iraqi military units, border patrol and paramilitary organizations so that the face of security will increasingly be an Iraqi face, not an American face."

Bush's news conference failed to stop criticism of his Iraq policy.

Democratic presidential hopeful Howard Dean said Bush "seems content to pursue the current flawed plan, unwilling to do what is necessary to encourage our friends and allies to assist, incapable of taking the steps necessary to expedite the transfer of sovereignty to the Iraqis and content to direct billions of dollars to special interests like Halliburton."

Sen. John Kerry, another Democratic candidate, said Bush "can talk about hardening targets, but still has failed to take the target off the backs of American soldiers. ... The only answer is to bring in other countries, share the burden and end the feeling of American occupation."

Bush said he wasn't bothered by criticism.

"I think the American people are patient during an election year, because they tend to be able to differentiate between politics and reality," he said. "As a matter of fact ... the electorate is a heck of a lot smarter than most politicians."

Bush said the United States was working closely with Syria and Iran to prevent foreign terrorists from crossing into Iraq. But State Department spokesman Richard Boucher said, "At times, we've seen a little bit of action. But, frankly, we've also made clear that, both in the case of Syria and of Iran, they need to do more."

The president drew a parallel between the suicide bombings in Iraq and the Sept. 11, 2001, terrorist attacks in the United States. "It's the same mentality," Bush said. He described the approach of terrorists this way: "We'll just destroy innocent life and watch the United States and their friends and allies, you know, crater in the face of hardship."

He said the strategy for dealing with terrorists is to have strike forces ready to move quickly as intelligence is gathered. Bush said the strategy will not change but the tactical response to "more suiciders driving cars will alter on the ground."

"More checkpoints, whatever they decide," Bush said, apparently referring to military commanders. "How to harden targets will change. And so we're constantly looking at the enemy and adjusting."

Later Tuesday, Bush welcomed American Muslim leaders and ambassadors from Muslim countries for an iftar dinner, the traditional breaking of the daylong fast during Ramadan.

"We will continue to support the people of Iraq and Afghanistan as they build a more hopeful future," he said. "And we will not allow criminals or terrorists to stop the advance of freedom. Terrorists who use religion to justify the taking of innocent life have no home in any faith."