Two armed Czech teenagers hijacked a jet in Prague Wednesday and reportedly demanded that it fly to the United States. They surrendered and freed their hostages - including a Hungarian diplomat - after the plane landed in Frankfurt.

No injuries were reported among the 10 passengers and at least four crew members aboard the Soviet-made Tupolev-154 when it reached Frankfurt, officials said.The hijackers released 82 passengers at Prague airport after speaking with Lajos Taba, the Hungarian consul-general, the Hungarian news agency MTI said. It said Taba traded himself for the passengers and was among those freed in Frankfurt.

The hijackers, who were armed with guns and carried a fake hand grenade, gave up at Frankfurt Airport when U.S. officials prevented the plane from taxiing onto adjoining U.S. military base.

A witness said a policeman collapsed during a shootout at Prague airport when the hijackers took a hostage and forced their way onto the aircraft.

Hans Neitze, chief spokesman for Frankfurt police, said, "We found the emptied casing of a bullet, and we assume that there was at least one shot fired on the aircraft."

Criminal investigator Roland Desch said the hijackers initially demanded to be flown "overseas" but were convinced by the crew that the plane could not fly that far. The plane then went to Frankfurt.

"We still don't know what their motive was," Frankfut police spokesman Karl-Heinz Wagner said, adding the youths were being questioned. He said the hijackers were armed with a sawed-off shotgun and a rifle and carried a fake grenade.

Wolfgang Schwalm, a spokesman at Frankfurt airport, said the hijackers gave up after officials refused to accept them at the U.S. Air Force's Rhein-Main Base, which is located at the airport.

A U.S. Air Force spokesman, Eberhard Bock, said the jet was halted on the taxiway by a military truck driven onto the tarmac.

"Two men got off the plane, and they were held by U.S. military security police until the German police arrived and took over," Bock said.

The jet had been en route to Amsterdam, said Hungarian radio, which was monitored in Budapest.

Witnesses at Prague's airport said two hijackers forced their way into the VIP lounge and took a female airport employee hostage. The two then forced their way onto the plane but left their hostage behind, the witnesses said.