OSLO, Norway (AP) _ Three Iranian men believed to be linked to a radical Islamic group commandeered a passenger jet over southern Russian today and diverted it to Norway.

The Tupolev-134 jet with 52 people aboard flew across the Baltic Sea and Sweden before landing at a small airport 25 miles north of Oslo, Norwegian news media reported. The flight from Kiev, Ukraine, took 3 1/2 hours.

Nearly 200 sheriff's deputies, police and anti-terrorist officers, some with dogs, converged on the terminal, along with 10 ambulances and four cars from the Russian Embassy.

''We will do anything we can to save the lives of these people,'' said embassy spokesman Yuri Mironov.

The plane was surrounded by 10 ambulances and the entire airport was darkened, Norwegian television said. ''We have a negotiating team there with interpreters ready to talk,'' said Berit Griebenow of the Justice Ministry. ''All we can do now is wait and see.''

The flight originated in Baku, capital of Azerbaijan, and was hijacked after a stopover in Russia - first flying to Kiev and then on to Oslo.

Alexei Kandaurov, a spokesman in Moscow for the Russian Security Ministry, said the hijackers were carrying hand grenades and explosives. He said they were thought to have links with the radical Iranian-backed group Hezbollah.

Ukrainian and Azerbaijani officials said the men were Iranian nationals.

Norway was the site of the breakthrough peace talks between Israel and the Palestine Liberation Organization. Radical Islamic groups have denounced the agreement.

The plane carried six crew members and 45 passengers - including one child - when it was hijacked, Kandaurov said. A Ukrainian navigator who speaks English and has international flying experience boarded the jet in Kiev. The Russian pilot, Capt. Mikhail Osavin, told authorities the hijackers threatened the crew with hand grenades and explosives, Alexei Zakharov of the Russian Security Ministry said.

The Azerbaijani capital has been gripped by political unrest in the past few months, including a government crackdown on Iranian-backed militants who have demanded that southern parts of Azerbaijan be united with northern Iran.

There is a substantial Iranian presence in Azerbaijan, where Iran has been sending preachers. In August, the Azerbaijani government crushed a 2-month- long rebellion by a colonel who was accused of being backed by Hezbollah.