SHANKSVILLE, Pa. – A passenger on United Airlines Flight 93 called on his cell phone from a locked bathroom and delivered a chilling message. “We are being hijacked, we are being hijacked!” Minutes later the jetliner crashed in western Pennsylvania with 45 people aboard, the last of four closely timed terror attacks across the country.

Radar showed the San Francisco-bound Boeing 757 from Newark, N.J., had nearly reached Cleveland when it made a sharp left turn and headed back toward Pennsylvania, crashing in a grassy field edged by woods about 80 miles southeast of Pittsburgh. There was no sign of survivors.

“There’s a crater gouged in the earth, the plane is pretty much disintegrated. There’s nothing left but scorched trees,” said Mark Stahl of Somerset, who went to the scene.

The Boeing 757 crash was one of four reported Tuesday by United and American Airlines. Two jetliners crashed into the World Trade Center in New York City and one hit the Pentagon in Washington.

A Virginia congressman said Flight 93’s intended target was apparently Camp David, the presidential retreat in the mountains of Maryland, about 85 miles southeast of the crash site.

United said Flight 93 left Newark at 8:01 a.m. with 38 passengers, two pilots and five flight attendants.

Minutes before the 10 a.m. crash, an emergency dispatcher in Pennsylvania received a cell phone call from a man who said he was a passenger locked in a bathroom aboard United Flight 93. The man repeatedly said the call was not a hoax, said dispatch supervisor Glenn Cramer in neighboring Westmoreland County.

“We are being hijacked, we are being hijacked!” Cramer quoted the man from a transcript of the call.

The man told dispatchers the plane “was going down. He heard some sort of explosion and saw white smoke coming from the plane and we lost contact with him,” Cramer said.

FBI agent Wells Morrison wouldn’t confirm the plane was hijacked, but said the FBI was reviewing the tape of the 911 call.

“At this point, we’re not prepared to say it was an act of terrorism, though it appears to be that,” Morrison said.

Rep. James Moran, D-Va., said after a Marine Corps briefing in Washington that Flight 93 apparently was intended for Camp David.

Reporters were taken to the top of a hill overlooking the scene. The crash left a V-shaped gouge in a grassy field surrounded by thick woods, just below a hilltop strip mine. The gouge is 8 to 10 feet deep and 15 to 20 feet long, said Capt. Frank Monaco of the Pennsylvania State Police.

Investigators believe the plane crashed there and disintegrated, sending debris into thick trees nearby, Monaco said.

“There’s nothing in the ground you can see,” Monaco said of the crash site. “It just looks like tiny pieces of debris.”

Michael R. Merringer was out on a mountain bike ride with his wife, Amy, about two miles away from the crash site.

“I heard the engine gun two different times and then I heard a loud bang and the windows of the houses all around rattled,” Merringer said. “I looked up and I saw the smoke coming up.”