New York Mud-spattered rescue crews, chanting "USA! USA!," got a morale-boosting visit Friday from President Bush as they searched in vain for signs of life in the ruins of the World Trade Center.
"Thank you for your hard work, thank you for making the nation proud," the president told the workers through a bullhorn.
Bush toured the disaster site on foot after getting a helicopter view of the devastation. He spoke to some of the workers, shook hands with others and was briefed by senior emergency officials. He was accompanied by Mayor Rudolph Giuliani and other New York politicians.
Bush noted that Friday was a day of remembrance for those killed in the attacks.
"America today is on bended knees in prayer for the people who died here, for the workers who work here, the families who mourn," he said.
Despite the appreciative visit, the grim reality was that for a second straight day, no survivors were found in the debris.
Occasionally, the crews halted all work to listen for any noise a sharp knock or muffled voice that might lead them to a survivor.
"When they call for silence on the pile ... it caused me to say a prayer every time," said volunteer Richard Coppo. "It meant there was a possibility a hope that we had found something."
But all they heard was silence. And then they resumed moving rubble 10,425 tons and counting.
More than 4,700 people remained missing. Just five people have been pulled alive from the ruins since two hijacked jetliners toppled the twin towers Tuesday.
The official death toll remained at 184, while the number of people injured including those injured in the rescue efforts climbed to 4,300, Giuliani said.
New York City's two airports, where a dozen people of Middle Eastern descent were detained and then released overnight, reopened Friday after an 18-hour shutdown. One person was still being questioned, but was not charged, said Barry Mawn, head of the FBI's New York office.
"We are running down hundreds, if not thousands, of leads around the country," Mawn said.
Newark International Airport, close to New York, also reopened.
Work at ground zero the enormous mass of wreckage created when the two skyscrapers crumbled was complicated by a ferocious overnight downpour that turned dust into mud and made even the simplest tasks more difficult and dangerous.
Workers who have battled fatigue and choking smoke were slowed by the muck. One worker reported finding mud-caked body parts.
The mayor did offer some good news: The Wall Street financial district closed off since the terror attacks should be back in business Monday. The stock markets, closed for the longest stretch since the crash of 1929, also are due to resume operations Monday.
The Staten Island ferry will start running again the same day, and city officials hope to reopen another slice of downtown to thousands of displaced residents, Giuliani said.
For the first time since the tragedy, the mayor said a few looters had slipped into the banned area of Manhattan below 14th Street. One man was arrested carrying $3,000 in watches from a Tourneau store.
In another incident, a woman dressed in medical scrubs and carrying a cell phone showed up at a police station insisting she had just spoken to her husband who was beneath the rubble. When her story proved false she also said her husband was a police officer and was with nine other survivors she was charged with reckless endangerment, obstructing fire operations and filing false reports.
"She's a nut," said Police Commissioner Bernard Kerik.
Kerik said several people had been arrested for using phony identification or pretending to be volunteers, then committing crimes in the cordoned-off disaster zone. And Giuliani said a phony telemarketer was soliciting bogus contributions for a nonexistent fund to help the families of victims.
"We'd really like to catch them and make an example of them," the mayor said.