An estimated 200 firefighters may have died and as many as 80 police officers were believed to be missing Tuesday after two planes slammed into the twin skyscrapers in lower Manhattan.

''We're going to have to bury a lot of people,'' said Mike Carter, vice president of the firefighters union. He estimated that half of the 400 firefighters who first reached the scene may be dead.

A police source, speaking on condition of anonymity, said 78 officers were missing, but Assistant Chief Tom Fahey said the number is not that high.

New York's Roman Catholic Cardinal Edward Egan - who administered last rites to a dozen victims - said the firefighters and police were ''dead in great numbers.''

Soot-covered and exhausted, some of the rescue workers embraced. Many had responded to the first blast at the north tower, only to shocked by a second explosion on the south tower less than 20 minutes later.

Up to 11,000 firefighters eventually responded to the attacks, with more arriving from outlying areas, said Harold Schaitberger, president of the International Association of Fire Fighters, speaking from Washington, D.C.

''Right now they're working their way through mountains of rubble. They're still fighting fires actively in other buildings associated with the World Trade Center complex,'' Schaitberger said.

Brian Stark, an ex-Navy paramedic who volunteered to help, said waiting rescue crews were warned to expect a high body count. He said the paramedics had been told that ''hundreds of police and firefighters are missing'' from the ranks of those sent in to respond to the initial crash.

Schaitberger feared the attacks will have killed more firefighters than any other in U.S. history. ''It's going to be a devastating number,'' he said.

One firefighter waiting for orders to deploy to the smoky rubble said he expected to find some of his colleagues among the dead.

''This is going to hurt,'' said Jack Gerber, a 43-year-old city firefighter. ''A lot of guys got killed today.''