WASHINGTON — As the nation formally ended 12 days of mourning yesterday, Bush administration officials cautioned Americans not to expect a massive military response to the Sept. 11 attacks but a silent and invisible diplomatic and financial campaign aimed at crippling terrorists.

Major developments • Secretary of State Colin Powell promises to lay out evidence so the world can see Osama bin Laden is guilty of terrorist attacks. • Defense Secretary Donald Rumsfeld confirms the United States has lost contact with an unmanned spy plane over Afghanistan but said he had no reason to believe Taliban fighters brought the plane down. • Washington has been denied use of a major Saudi Arabian air base for an offensive against terrorism, a Saudi official says. • Taliban leaders say they can't find bin Laden to advise him to leave the country. U.S. officials dismiss the claim. • Tens of thousands of people gather in New York's Yankee Stadium to pray for the missing and dead. • President Bush returns the American flag to full staff at Camp David, symbolically ending the period of national mourning. • A Defense Department team arrives in Pakistan to discuss military cooperation in a possible strike against bin Laden's network. • The Federal Aviation Administration imposed a one-day ban yesterday on crop-dusting from airplanes in domestic airspace over concerns about possible chemical-weapons attacks. • The number of missing at World Trade Center is 6,453; confirmed dead 261. Death toll at Pentagon: 189. Pennsylvania crash: 44.

Secretary of State Colin Powell said the Bush administration is producing a document that will contain compelling evidence showing that Saudi exile Osama bin Laden and his global terrorist network, al Qaeda, were responsible for the devastating attacks against the World Trade Center and the Pentagon.

"I think in the near future, we'll be able to put out a paper, a document, that will describe quite clearly the evidence that we have linking him to the attack," Powell said on the NBC news program "Meet the Press."

The administration scoffed at Taliban claims that bin Laden cannot be found.

The remarks by Powell and other administration officials were part of an effort to portray a calm, methodical response to the terrorist assaults, buying time for the administration from a public craving revenge.

"The campaign has begun," Powell promised in remarks to two television networks yesterday. He was echoed by Defense Secretary Donald Rumsfeld and national-security adviser Condoleezza Rice.

The assurance that the government is acting — even if the actions aren't yet visible — came as Americans struggled to return to daily rituals. The National Football League resumed play yesterday after skipping last week. Thousands of mourners attended a prayer service at Yankee Stadium in New York. Led by Oprah Winfrey and James Earl Jones, Christian, Jewish and Islamic leaders offered prayers, and political leaders recalled the heroism of the city's emergency workers.

Meanwhile, the number of people believed missing in the rubble of the World Trade Center increased to 6,453 yesterday as rescue workers continued sifting through smoldering debris and uncovered a 10-foot piece of jetliner fuselage.

The hundreds of firefighters, police and construction workers combing the wreckage have not found the flight recorders, or black boxes, of the two hijacked airliners. Pictures have been posted throughout the site so rescuers can recognize them.

The piece of fuselage was loaded onto a golf cart and taken away by federal crime-scene investigators.

Mayor Rudolph Giuliani said the increase in the missing, up from 6,333 on Saturday, was a result of list revisions.

At Camp David, the president and first lady put their hands to their hearts as Marines raised the American flag to full staff while the Marine band played a drum roll and "The Star-Spangled Banner." The three-minute ceremony formally ended the government-declared mourning period, during which flags flew at half-staff.

But war preparations and security concerns stemming from the investigation into the attacks made clear that events were far from normal.

A senior defense official confirmed yesterday that Rumsfeld signed a deployment order late Saturday that would dispatch an undisclosed number of logistics units overseas to support previously deployed special forces and Air Force units flying F-15E fighter-bombers, F-16 fighters, B-1 long-range bombers, E-3 AWACS airborne command-and-control aircraft, refuelers and other support aircraft.

Rumsfeld deployed those Air Force units five days ago. The U.S. Army Special Operations Command received a deployment order signed by Rumsfeld on Friday.

On ABC News' "This Week," Powell denied a report in Saturday's Washington Post that he was trying to persuade the Saudi government to reverse its policy of refusing to allow the United States to engage in offensive air strikes from Saudi bases. A reversal would allow the Pentagon to direct air operations against terrorist groups from a new operations center at Prince Sultan Air Base.

Powell said the Saudis "have been providing everything we have asked of them so far."

In Japan, the Jiji news agency quoted Japanese government sources as saying the Bush administration had warned allies of the possibility of more attacks this week using means that could be "more cruel and shocking" than the first attacks. Speaking on ABC, Powell said: "I'm not familiar with that particular report, but I think we have to be vigilant during this time of heightened tension."

In another development reflecting the gaps in government intelligence about terrorists, investigators said they now believe four of the 19 hijackers from Sept. 11 had assumed stolen identities going back years and had lived in this country without their true identities becoming known.

President Bush, who spent the weekend at Camp David with his friend Commerce Secretary Donald Evans, returned to the White House in midafternoon and declined to make public remarks.

Bush's national-security team, in a series of appearances on talk shows yesterday, sought to reassure the country that plans were moving ahead even if not visible.

"Is it likely that an aircraft carrier or a cruise missile is going to find a person? No," Rumsfeld told reporters yesterday. "This is going to happen over a sustained period of time because of a broadly based effort where bank accounts are frozen, where pieces of intelligence are provided and where countries decide that they want to change their policies."

Previous administrations have attempted similar efforts to restrict terrorist funds with limited success. But Bush aides expressed hope, as Rice told CNN, of "really squeezing the life blood out of this organization" with an executive order the White House is preparing. The order would designate various groups and individuals as terrorists, freezing their assets in the United States.

Of a report from the Taliban's official Bakhtar news agency Saturday that a U.S. aircraft had been shot down near the Uzbekistan border, Powell, speaking on ABC, said: "I would rather not talk about what might or might not have been downed."

Rumsfeld confirmed the Pentagon had lost contact with an unmanned aerial- reconnaissance drone over Afghanistan but said, "We have no reason to believe it was shot down."

Rumsfeld, on CBS' "Face the Nation," said the United Arab Emirates' breaking of diplomatic relations with the Taliban was a victory for the U.S. efforts.

Information from The Associated Press is included in this report.