Four hijackers were in Soviet custody Monday after being returned from Israel, and Soviet authorities praised the actions that gained the release of 30 young hostages and ended a two-day drama without bloodshed.

The hijackers arrived at Moscow's Sheremetyevo airport before dawn Sunday. Vremya, the evening television news program, showed the men being hustled off a plane into waiting cars.The state-run media did not say what charges the four would face or where they were being held. The reports gave detailed accounts of the hijacking, which began Thursday when the group seized a school bus filled with children in the southern Russian city of Ordzhonikidze.

In return for the release of the 30 children, their teacher and the driver, authorities gave the hijackers a plane and a crew and allowed it to fly to Israel on Friday.

Israel and the Soviet Union, which have not had diplomatic relations for 21 years, worked together to end the incident. The hijackers surrendered after the plane landed at Ben-Gurion International Airport, and a Soviet plane was sent to pick them up.

"The outcome of the operation will serve as a warning to those who may nurture this kind of criminal designs," Tass quoted a KGB secret police spokesman as saying.

"It is for the first time that such an operation has been carried out with the participation of another state. And its results can be described as successful: the criminals have been captured, they will sustain a deserved punishment and, what is the main thing, the children were rescued," he was quoted as saying.

Media reports identified the leader of the gang as 38-year-old Pavel Yakshiyants, who was convicted three times for robberies and theft. Geni Ageyev, a deputy KGB chairman, described him as a "hardened, habitual criminal," Tass said.

Tass indicated a fifth person, 29-year-old Tamara Fotaki, was a virtual hostage herself and accompanied the hijackers onto the plane "for the sake of saving the lives of the children and their teacher."

The government newspaper Izvestia said the children were on a field trip when the hijackers captured them.

"At the exit, near the gate, they saw a bus. The driver hospitably opened wide the doors and said, `They sent us for you.' The children, not thinking, entered the bus. And all the rest developed like a detective story," Izvestia said.

Pravda, the Communist Party newspaper, said the hijackers gradually released children as demands were met for vinegar, apparently to dissolve drugs, medication "guaranteeing a high," and weapons.

Negotiations were led by Evgeny Sheremetyev, a KGB official from nearby Stavropol, Soviet President Mikhail Gorbachev's home area.

After their demands were met for a large quantity of foreign currency, the hijackers held only 11 of the children hostage, Pravda said. Sheremetyev then offered himself in exchange for the rest and was forced to lie on the floor of the bus while the plane was prepared for the hijackers.

The strategy was in sharp contrast to tactics used in a Soviet hijacking in March, when soldiers stormed a plane held by members of a family jazz band from the Siberian city of Irkutsk.

Five of the hijackers, three passengers and a flight attendant died, and much of the plane was reduced to ashes by a bomb set off by the hijackers.