"We're at war," Bush declared as he convened a meeting at Camp David with senior advisors to plot what he said would be a "sweeping, sustained and effective" campaign to eradicate terrorism.
In an effort to nail down that diplomatic commitment, Bush spoke Saturday by telephone with Pakistani President Gen. Pervez Musharraf. White House officials described it as a "good conversation" and "a positive sign" that the alliance is coming together.
The State Department earlier last week presented a list of demands to Pakistan, including access to intelligence data, help in identifying Bin Laden's network and agents, and clearance to use Pakistan's airspace.
Complying with an earlier request, Pakistan already has begun closing its border with Afghanistan.
In Washington, Pakistani Ambassador Maleeha Lodhi said Saturday that her country had "absolutely accepted" the long list of specific requests by the Bush administration.
"We conveyed to the U.S. administration that Pakistan will firmly support whatever the U.S. has asked or proposed to us. We have said we will cooperate accordingly."
But in Pakistan, the message was more ambiguous, with government officials saying they are merely "in the process of discussions" with the United States and have committed only to an agreement in principle.
The conflicting characterizations reflect the competing pressures on countries being recruited into the U.S. alliance. In Pakistan, there is deep public skepticism about taking sides with a distant superpower in an endeavor with potentially bloody repercussions for the region.
Indeed, Afghanistan's Taliban regime Saturday threatened to wage war on neighboring countries that grant the United States use of airspace or military bases.
At Camp David, the Maryland presidential retreat about 60 miles northwest of Washington, Bush met for 2½ hours with his National Security Council. He also met with smaller groups of advisors during the afternoon and later dined with his senior national security team.
A day after touring the rubble in Manhattan--where 4,972 people are still missing amid the wreckage of the World Trade Center towers--Bush spoke in the most forceful language he has used since Tuesday's attacks, which began when terrorists hijacked four U.S. commercial jetliners.
Two of the planes slammed into the twin towers in New York, toppling both; a third plane hit the Pentagon and the fourth--apparently bound for Washington, D.C.--crashed in a Pennsylvania field.
Each day since the suicide missions, Bush has honed his public message, ramping up his language and increasingly making clear his determination to not just punish those who helped perpetrate the attacks but to wage a war against terrorism.
So it was on Saturday, as he discussed his administration's evolving plans in his weekly radio address and later in a give-and-take session with reporters. He cautioned the American people against expecting immediate action and quick success, to be prepared to show patience, and to sacrifice, "for the conflict will not be short."
"Victory against terrorism will not take place in a single battle," Bush said, "but in a series of decisive actions against terrorist organizations and those who harbor and support them."
Bush moved closer to placing direct blame for the attacks on Bin Laden, an Islamic fundamentalist suspected of masterminding the 1998 bombing of two U.S. embassies in Africa.
Responding to a reporter's query, Bush said, "There is no question he is what we would call a prime suspect. And if he thinks he can hide and run from the United States and our allies, he will be sorely mistaken." Others in the administration previously had named Bin Laden, but Bush had not publicly done so.
Leaving behind the teary mien of earlier last week, when he had spoken of his prayers and his concern for the families of the victims, Bush referred to those who carried out the hijacks as "barbarians" and repeatedly vowed to track down those who helped organize the attacks.
"They will try to hide, they will try to avoid the United States and our allies--but we're not going to let 'em," he said. "They run to the hills; they find holes to get in. And we will do whatever it takes to smoke 'em out and get 'em running. And we'll get 'em."
In an echo of his father, the 41st president, after Iraq invaded Kuwait in 1990, Bush said: "This act will not stand." An international military coalition cobbled together by the United States ousted Iraqi troops from Kuwait in early 1991.
In comments later in the day, White House Press Secretary Ari Fleischer would not rule out any line of assault against terrorists and their supporters, including the use of ground combat troops.
But Fleischer stressed that Bush would not be rushed. "There is no question America is rallied and ready," he said. But "the president will only act when the time is right."
Congressional leaders, meanwhile, turned their attention to looming economic crises, including severe financial hardships facing the U.S. airline industry.
Continental Airlines announced plans Saturday to lay off 12,000 workers. It and Northwest Airlines also said they will slash their permanent flight schedules by 20% in the wake of the attacks.
Other airlines have reported plummeting demand for seats, and security concerns have slowed to a crawl the flow of passengers through the nation's airports.
House leaders said Saturday they hope to push through a $15-billion bailout for the industry when Congress reconvenes Thursday from a recess honoring this week's Jewish holidays. The package includes $2.5 billion in grants and $12.5 billion in loan guarantees.
John Feehery, spokesman for House Speaker J. Dennis Hastert (R-Ill.), said the bailout tops a list of emergency economic measures Congress will tackle in the coming weeks.
Rescue teams continued their frantic search for survivors in New York and at the Pentagon in Virginia, where close to 200 people who were either on the hijacked plane or working in the military complex are believed to have perished.
Pentagon officials said Saturday that if not for recent measures taken at the sprawling structure to improve safety, the death toll could have been much higher.
As many as 4,500 people may have been in the vicinity at the time, about 800 of them in the area immediately around the plane, the rest close enough to be affected by the smoke and flames of the fire set off by the crash, said Lee Evey, program director of the Pentagon renovation.
If the Pentagon had not been in the midst of moving people out of that part of the building as part of a $1-billion renovation project, twice as many people likely would have been working there, Evey said.
A few miles away from that crash site, an array of the capital's leaders gathered Saturday for the funeral of one of the passengers aboard the plane that struck the Pentagon: Barbara Olson, a conservative TV commentator and wife of U.S. Solicitor Gen. Theodore B. Olson.
"This is indeed a sad occasion," Supreme Court Justice Clarence Thomas said in his eulogy, "one to be repeated thousands of times by our fellow citizens across the country."
In the Democrats' weekly radio address, New York Democratic Sens. Charles E. Schumer and Hillary Rodham Clinton expressed deep gratitude for the nation's outpouring of grief and support in the wake of Tuesday's tragedies.
Clinton said the attacks on the Pentagon and World Trade Center represented "an attack on America and our values."
"We will show the world," she said, "that though buildings can crumble, and innocent people sacrifice their lives, America and New York remain strong, our democracy is intact, our faith in God and in each other secure."
Times staff writers Robin Wright and Esther Schrader contributed to this story.