WASHINGTON —The Bush administration proclaimed significant progress in the war on terror yesterday but said the enemy has adjusted to American defenses and that “America is safer, but we are not yet safe.”

Releasing an updated counterterrorism strategy in advance of a speech that President Bush was to deliver later in the day, the White House said: “The United States and our partners continue to pursue a significantly degraded but still dangerous Al Qaeda network.”

“Yet the enemy we face today in the war on terror is not the same enemy we faced on September 11, [2001],” the 23-page terrorism strategy update said. “Our effective counterterrorist efforts in part have forced the terrorists to evolve and modify their ways of doing business.”

The White House also rejected Democrats’ calls for replacing Defense Secretary Rumsfeld. “It’s not going to happen,” presidential spokesman Tony Snow said. “Creating Don Rumsfeld as a bogeyman may make for good politics but would make for very lousy strategy at this time.”

Two months before the midterm elections, the report was the White House’s latest attempt to highlight national security, an issue that has helped Republicans in past campaigns. Democrats were releasing their own assessment.

“Years of failed Republican policies have made America less safe and less able to effectively fight terrorism, and Democrats are ready to take this country in a new direction,” Democrats said in statement.

The updated White House strategy came in the wake of the release of a new Al Qaeda video over the weekend that raised concerns about the possibility of another attack as the fifth anniversary of September 11 approaches. The tape featured an American — believed by the FBI to have attended Al Qaeda training camps — calling for his countrymen to convert to Islam.

Asked about this yesterday, a special assistant to Mr. Bush for homeland security and counterterrorism, Fran Townsend, said she did not think the tape suggested another strike.

“We’ve seen tapes before. We’ve seen these sort of releases right near September 11,” she said on ABC’s “Good Morning America.”

“There are no plans to raise the threat [terror] threat level,” Ms. Townsend said.

The Department of Homeland Security had raised the terror threat for aviation to red — its highest level — in mid-August at the time the British, working with Americans, broke up what was purported to be a plot against international flights bound for America from Britain.

The administration’s Iraq war policy and terrorism strategy have come under increasing criticism in recent months, and Republicans and Democrats returning to Capitol Hill yesterday for the fall season were set to debate the strategy as the midterm elections draw near. Five years after the attacks on the World Trade Center in New York and the Pentagon, about a third of the American people think the terrorists are winning, according to a recent AP-Ipsos poll.

In its updated terror-fighting strategy, the administration took credit for some successes, saying that “we have deprived Al Qaeda of safe haven in Afghanistan and helped a democratic government rise in its place. It also said that “a multinational coalition joined by the Iraqis is aggressively prosecuting the war against the terrorists in Iraq.”

But it also acknowledged continuing challenges:

• “Terrorist networks today are more dispersed and less centralized. They are more reliant on smaller cells inspired by a common ideology and less directed by a central command structure.”

• “While the United States government and its partners have thwarted many attacks, we have not been able to prevent them all. Terrorists have struck in many places throughout the world, from Bali to Beslan to Baghdad.”

• “While we have substantially improved our air, land, sea, and border security, our Homeland is not immune from attack.”

• “The ongoing fight for freedom in Iraq has been twisted by terrorist propaganda as a rallying cry.”

Mr. Bush has said on many occasions that the country must be prepared for a drawn-out battle against a new kind of enemy, and the new counterterrorism strategy released yesterday says flatly that “the war on terror will be a long war.”

It says that among the strategies that America must emphasize are making all sovereign nations accountable for what happens on their soil, strengthening existing coalitions and partnerships against terrorists, and continue to develop more expertise in this area.

One particular problem, it noted, is an “increasingly sophisticated use of the Internet and media” by terrorists and would-be terrorists, saying these tactics have allowed enemies of America to “rally support, proselytize, and spread their propaganda without risking personal contact.”

It also maintains that terrorism “is not simply a result of hostility to U.S. policy in Iraq.”

“The United States was attacked on September 11 and many years earlier, well before we toppled the Saddam Hussein regime,” it said. “Moreover, countries that did not participate in coalition efforts in Iraq have not been spared from terror attacks.”

“There will continue to be challenges ahead, but along with our partners, we will attack terrorism and its ideology and bring hope and freedom to the people of the world,” the policy statement said.

“This is how we will win the war on terror.”