They filed in wearing everything from jeans and T-shirts advertising their places of origin -- Georgia, Charlotte -- to the smart, forest green uniforms of the Palm Beach County Sheriff's Office and the daunting black of the Ohio State Highway Patrol.

For two days, they will be city of Pittsburgh police.

Mayor Luke Ravenstahl yesterday swore in about 1,000 visiting law enforcement agents for service in the city during the G-20 Summit in a ceremony at Soldiers & Sailors Memorial Hall & Museum in Oakland.

"We're certainly very happy that you're here, very honored that you're here, and very eager to use you to make sure we keep our city safe" for 48 hours, the mayor said, before swearing the officers to uphold the laws of the nation, state and city.

"They're here because they were recommended by their police chiefs," the mayor said. Pittsburgh Police Chief Nate Harper called them "the A Team." Language in the contract between the city and those agencies bars officers with recent disciplinary problems from joining the G-20 force.

Earlier, Public Safety Director Michael Huss would not describe their role, but said they would be located throughout the city, and perhaps the region, and would be well taken care of when they're not working long shifts.

"There's one heck of a plan out there and one heck of an apparatus to care for these folks," he said. "We're going to try to give them hot, catered meals when we can, but we have also gone to the extent of having [military rations] and things, too."

Mr. Ravenstahl said they would be working 12 hours on, 12 hours off, like city officers.

Huge contingents from Chicago and Philadelphia filed in, the former largely in T-shirts, the latter in full uniform. A few officers wore shirts honoring the Fighting 5th Zone, which recently lost three of its number in the Stanton Heights shooting.

Others came from state agencies, like the Illinois Law Enforcement Alarm System, the Alabama Department of Public Safety, and the Massachusetts Bay Transit Authority.

Others are from county or regional entities, like the Allegheny County Housing Authority, Armstrong County, Indiana County, the Washington County district attorney's office, Pocono Mountain Regional Police Department, the Cuyahoga County [Ohio] Sheriff's Office, and the Washington Metropolitan Area Transit Authority.

Contributing big cities include Baltimore, Charlotte, Cleveland, Harrisburg, Louisville, Ky., and Tucson, Ariz.

Smaller Pennsylvania municipalities that sent officers include Beaver Falls, Buffalo Township, Clairton, Coraopolis, Harrison Township, Latimore Township, Middlesex, Monongahela, Monroeville, New Castle, Rankin, Reading, Tyrone, Whitehall and Whitaker.

Beallsville Borough Police Chief Richard Young is the only officer with his Washington County town, and he sent himself, after making sure the state police would look out for the 511 people under his protection.

"It basically comes down to the point that it's a huge task, to keep the city secure, so everybody needs to be involved," Chief Young said in a phone interview. "In our line of work, we're all brothers, so we help each other."

Getting the officers from more than 40 jurisdictions lined up was no easy task.

The city secured a guarantee of $10 million in federal funds to cover their pay and other expenses, got council approval for the expense, worked out contracts with each agency, and declared a state of emergency to legally facilitate the process of deputizing them.

The city also entered into a contract to buy insurance, largely to cover any liabilities stemming from the actions of visiting officers. It will pay as much as $3 million for that and other policies in effect for nine days before, during and after the Thursday and Friday meeting of world leaders.

Mr. Ravenstahl said that the number of city officers, out-of-towners, and state troopers is "approaching 4,000."

"I'm not going to talk numbers, but we've reached what we feel we need," Mr. Huss said. "We've got National Guard folks that will help us also. ... We have I think over 2,400 National Guard folks that are going to assist us."