MOSCOW (AP) _ A Soviet icebreaker arrived Saturday at an iced-over strait of the Bering Sea where more than 1,000 white whales have been trapped for a month, but the crew wasn't sure the whales would follow the ship out to the open sea, the Communist Party newspaper Pravda reported Saturday.

A separate newspaper report Saturday in Rural Life (Selskaya Zhizn) said about 40 whales have died since they were first sighted Jan. 29, despite efforts of fur trappers from the nearby Chukotskiy Peninsula to feed the animals and keep some areas free of ice for them to move around.

The official news agency Tass said the Soviet icebreaker Moskva (Moscow) began its rescue operation on Feb. 7, and Pravda said the ship reached the whales Saturday. The paper said the crew was trying to determine how to get the whales to follow the ship's path back out to open sea, as more ice closed in behind the vessel.

''The sailors are doubtful,'' Pravda said.

Pravda quoted Alfred Berzin, chief of the whale studies laboratory of the Pacific Scientific Research Institute of the Fishing Industry and Oceanography, as saying he wasn't certain the rescue attempt would succeed.

''These whales, of course, are easily frightened, but at the same time they are peaceful and in natural conditions they freely swim alongside ships,'' Berzin was quoted as saying.

He said white whales are accustomed to Arctic conditions and might be able to make their way to freedom by breathing through the thin ice openings. But he said the whales, which are mammals, must surface for air every 60 to 90 seconds.

''Who knows?'' Berzin said. ''Maybe they will follow the trail of the icebreaker.''

Rural Life reported workers from a fur trapping collective on the Chukotskiy Peninsula were using tractor-towed sledges to haul frozen fish to feed the whales, but that about 40 had died.

Pravda said Moskva's captain, A. Kovalenko, reported extreme difficulty in breaking open some sections of the path toward the trapped whales. He said that at one point, the ship advanced only 200 yards in four hours.

An earlier report in the government newspaper Izvestia said the whales became ensnared in the ice after following a large shoal of Arctic fish into the shallow waters of the Strait of Senyavin.