WASHINGTON (AP) — A solemn President Bush returned the American flag to full staff Sunday as the United States promised to lay out evidence making Osama bin Laden's guilt in the terrorist attacks "very obvious to the world." The administration scoffed at Taliban claims he cannot be found.

Secretary of State Colin Powell said the government would "put before the world, the American people, a persuasive case that ... it is al-Qaida, led by Osama bin Laden, who has been responsible."

Administration officials and congressional leaders turned their appearances on Sunday's TV talk shows into a two-pronged effort to show the government's resolve to choke off the terrorists and to encourage Americans to return to a more normal routine — crucial to getting the recession-bent economy moving again.

As the U.S. military got ready to strike, Defense Secretary Donald H. Rumsfeld suggested that brute force may not be the best way to get at bin Laden.

"Is it likely that an aircraft carrier or a cruise missile is going to find a person?" Rumsfeld asked reporters. "No, it's not likely; that isn't how this is going to happen."

Rather, he said, "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 xolitics."

Nonetheless, U.S. forces around the world were being repositioned. A Defense Department team arrived in Pakistan to discuss military cooperation in a possible strike against bin Laden's network.

"What we've been doing is getting our capabilities ... arranged around the world, so that at that point where the president decides that he has a set of things he would like done, that we will be in a position to carry those things out," Rumsfeld said on CBS' "Face the Nation."

He confirmed the United States had lost contact with an unmanned aircraft over Afghanistan but said he had no reason to believe the plane was brought down by Taliban fighters, as they claimed.

Administration officials rejected claims of Afghanistan's ruling Taliban that bin Laden could not be located. "It's just not believable that the Taliban do not know where the network can be located and found and either turned over or expelled," Rumsfeld said.

Powell said that even as military forces deploy and U.S. diplomats enlist other nations in a campaign against terrorists, Americans need to show their resilience by resuming ordinary activities.

"We need to get back to work," he said on ABC's "This Week." "We need to get back to ball games. We need to show the world that America is strong."

Without words, Bush sought to send the same message. In a ceremony at the Camp David presidential retreat, Bush placed his hand over his heart as the flag was raised to full staff for the first time since the Sept. 11 attacks on New York p..;ashington. Flags around the nation were returning to full staff in keeping with a proclamation Bush signed on the day of the attack.

Professional football did resume Sunday for the first time since the attacks, but in ways large and small, signs abounded that all was not normal.

—The Federal Emergency Management Agency reported that nearly 7,000 federal workers were helping with ongoing recovery operations in New York and Virginia, with bodies and debris still being removed from the World Trade Center and the Pentagon.

—Concerned about possible chemical weapons attacks, the Federal Aviation Administration imposed a one-day ban Sunday on crop-dusting from airplanes in domestic airspace.

—Tens of thousands of people gathered in New York's Yankee Stadium to pray for the missing and dead, passing through tight security that included police officers positioned on the stadium's light stanchions.

Powell detailed the diplomatic effort to assemble a worldwide campaign against bin Laden's network. He disputed suggestions that Saudi Arabia had denied the U.S. military permission to launch attacks from a Saudi base.

"They have been very responsive to all the requests we have placed on them," Powell said on "Meet the Press" on NBC. "But I don't want to go into what we have not yet asked of them."

He said the U.S. decision Saturday to lift sanctions imposed after the two nations tested nuclear weapons in 1998, shows that "we will stand by our friends who stand by us..