A federal judge in Cleveland yesterday granted Israel's request for the extradition of John Demjanjuk, a retired auto worker accused of being "Ivan the Terrible," who allegedly was responsible for the deaths of thousands of Jews at the Nazi death camp in Treblinka, Poland.

The case marks Israel's first victory in an effort to gain custody of an alleged war criminal since the United States and Israel signed an extradition treaty in 1963. Under Israeli law, Demjanjuk could be executed if he is found guilty.

Allan A. Ryan Jr., the former head of the Justice Department's Nazi-hunting Office of Special Investigations, said he believes that the Israelis were using Demjanjuk as a test case.

"They chose him because he was among the worst," he said. "Now that extradition has been granted, I believe we may see more requests from Israel."

The only other major Nazi war criminal case handled by Israel was that of Adolph Eichmann, who was kidnaped by the Israelis from Argentina. He was tried, convicted and executed in the early 1960s.

Israel has asked for extradition of other suspected Nazi war criminals from South America, but the requests have been denied on the grounds that Israel was not a sovereign nation at the time of the crimes and lacks jurisdiction.

In his decision yesterday, U.S. District Court Judge Frank J. Battisti ordered Demjanjuk's immediate arrest, but delayed the extradition until May 1 to allow him an opportunity to appeal.

Demjanjuk, 65, of Seven Hills, Ohio, allegedly ran the gas chamber at Treblinka, where 900,000 Jews were killed in 1942 and 1943. The camp was closed in 1943 following an uprising by the inmates.

Assistant Attorney General Stephen S. Trott said yesterday that evidence in the case, including testimony by eyewitnesses, shows that Demjanjuk worked for the German SS as an armed camp guard and gas chamber operator.

The Justice Department had alleged that Demjanjuk became known to prisoners as "Ivan the Terrible" because of his sadistic behavior.

At a March 12 hearing, government attorneys, acting at Israel's request, presented affidavits from Holocaust survivors' saying a photograph on Demjanjuk's 1951 U.S. visa is that of the death camp guard.

"Ivan had a weapon, a pipe, a sword, a whip, and he tortured Jews before they went into the gas chamber," said an affidavit of Elijahu Rosenberg, a death camp survivor. The affidavit said that "Ivan" crammed hundreds of people into the gas chambers and then turned on the motors that sent poison gas spewing in.

Other affidavits said Demjanjuk clubbed Jews to death with a pipe.

Demjanjuk's attorneys contended that their client is not "Ivan the Terrible."

They also argued that Demjanjuk, who came to the United States in 1952, could not be extradited because he has violated no U.S. law. The lawyers said Demjanjuk was charged with murder as a Nazi collaborator, which is not a specific crime in the United States.

Demjanjuk, a Ukrainian who served in the Soviet Army, said he was captured by the Germans and was a prisoner during World War II.

He lost his U.S. citizenship after a 1981 denaturalization trial before Battisti, who ruled that Demjanjuk lied on immigration papers to conceal his past as a death camp guard. Last year he was ordered deported by the U.S. Immigration Court, and the Justice Department moved to send him to the Soviet Union. That case is being appealed.