WASHINGTON/NEW YORK (Reuters) – President Bush vowed on Saturday to “smoke out of their holes” those behind this week’s attacks on the United States, as rescue workers sifted 450,000 tons of rubble and lifted body parts from New York’s World Trade Center, where thousands are entombed.

Bush for the first time said the United States was “at war,” singling out Saudi-born militant Osama bin Laden, based in Afghanistan under the protection of its radical Islamic government, as a prime suspect behind the attacks.

Invoking words made famous by his father, former President George Bush, shortly after Iraq invaded Kuwait in 1990, the president said: “This act will not stand. We will find those who did it. We will smoke them out of their holes, we’ll get them running, and we’ll bring them to justice.”

As fearful Afghans began fleeing the country, neighboring Iran prepared to seal its borders against an expected flood of refugees. Afghanistan’s hardline Taliban rulers, meanwhile, threatened holy war against anyone helping Washington launch attacks on their country.

The number of missing in New York’s World Trade Center climbed to 4,972, or 255 more than estimated on Friday, according to Police Commissioner Bernard Kerik.

Remains of 152 people have been recovered and 92 of those have been identified, he said. Only five people have been pulled out alive, two on Tuesday and three on Wednesday.

A few blocks from the ruins, Wall Street successfully tested its systems in readiness for a reopening of stock exchange trading on Monday after its longest closure since World War One.

“Our systems are all go,” New York Stock Exchange Chairman Richard Grasso said. The NYSE, the world’s largest stock market, was undamaged, he declared.

Trading is sure to be volatile. Amid growing fears the crisis could deal a heavy blow to the U.S. and world economy, Continental Airlines, the nation’s fifth largest airline, said it would immediately reduce its long-term flight schedule by about 20 percent and lay off about 12,000 employees. It said it was losing $30 million a day.

Northwest Airlines, the nation’s number four carrier, also said it was cutting its schedule by 20 percent and reviewing staffing. The administration said Transportation Secretary Norman Mineta would meet airline executives on Monday to discuss their problems.

BUSH: LONG CAMPAIGN

In his weekly radio address and in comments to reporters, Bush stepped up his rhetoric to its highest pitch since Tuesday’s attacks on the World Trade Center and the Pentagon, which have left hundreds confirmed dead and almost 5,000 people still unaccounted for.

“We are planning a broad and sustained campaign to secure our country and eradicate the evil of terrorism, and we are determined to see this conflict through,” Bush declared.

“I will not settle for a token act. Our response must be sweeping, sustained and effective. … You will be asked for your patience, for the conflict will not be short. You will be asked for resolve, for the conflict will not be easy. You will be asked for your strength because the course to victory may be long,” the president said.

Bush spoke for the first time about bin Laden, who has devoted his fortune to attacking U.S. targets in the name of a radical anti-Western ideology, calling him “a prime suspect … If he thinks he can hide from the United States, and our allies, he will be sorely mistaken.”

At least 190 people are believed to have died when hijackers crashed a third plane into the Pentagon near Washington. Forty five more died in a fourth plane that crashed in Pennsylvania after passengers fought with hijackers and foiled their plan to crash into another landmark building.

The cockpit voice recorder retrieved from the wreckage was in ”fairly good condition,” investigators said on Saturday,

In a Newsweek poll, 71 percent of respondents backed a U.S. military strike against terror bases and the countries that support them, even if there were a high likelihood that civilians would also be killed.

In New York, meanwhile, where the heart-breaking work of excavating the wreckage continued, family members of the missing were asked to bring in hairbrushes, toothbrushes or clothing of their loved ones to help in DNA identification of body parts.

STILL HOPE

There was a faint hope some people could still be alive in cavities within the 450,000 tons of rubble, said Commissioner Kerik.

“If you look at other disasters or tragedies around the world, people have been pulled out from these things five to six, seven days later and still alive. We’re not going to give up hope.”

Stepping up diplomatic efforts to build an international coalition for the forthcoming military campaign, the United States secured the crucial agreement of Pakistan, which borders Afghanistan, to back its efforts.

The United States has sought from Pakistan permission for military overflights and a closing of its border with Afghanistan, among other requests.

“We put before the Pakistan government a specific list of things we would like cooperation on and they have agreed to all those items,” said Secretary of State Colin Powell.

For its part, Pakistan said it would comply with U.N. Security Council resolutions on the terror attacks. “The government will discharge its responsibilities under international law,” Foreign Minister Abdul Sattar said, adding he did not expect Pakistan to take part in military operations outside its borders.

Washington’s message to other nations, including Arab and Islamic states, is that they must choose sides. In the coming storm, they are being told they must either back the United States or risk diplomatic and economic isolation.

NATION WRAPPED IN MOURNING

India signaled it was ready to let the United States use its military facilities and could provide a large base for any military strike at Afghanistan. But U.S. jets would still have to cross Pakistani air space to reach Afghanistan.

Russia and France voiced caution. Russian President Vladimir Putin said, “We must weigh up our decisions and make them on the basis of proven facts.”

Bin Laden, speaking through aides, this week denied involvement in the carnage, but described it as “punishment from almighty Allah.”

At home, the FBI said it had logged about 5,200 calls to a hotline set up for tips on Tuesday’s attacks and was adding additional telephone lines to handle the flood of calls.

Meanwhile, the nation remained wrapped in mourning. Most weekend sporting events were canceled, including Major League baseball and National Football League play — which never happened throughout World War Two or in response to the 1963 assassination of President John F. Kennedy.

Commercial flights resumed, but at less than half their former capacity.

The FBI on Friday named 19 hijackers, including seven pilots, who commandeered the four airliners used in Tuesday’s terror attacks, sought to question more than 100 people and made the first arrest in the investigation, a witness said to have “material” information on the suicide attacks.

Defense Secretary Donald Rumsfeld activated 35,000 reservists out of 50,000 authorized by Bush to provide “strike-alert” jet fighter protection and perform other duties at domestic military bases.