MOSCOW (AP) _ Soviet authorities have arrested the captains of the two ships that collided in the Black Sea and left 398 people dead or missing, a senior official said Thursday.

Official newspapers said the collision was caused by carelessness on the part of the ships' crews.

Albert I. Vlasov, first deputy chief of the Communist Party propaganda department, told a news conference that the cruise ship Admiral Nakhimov sank in just seven to eight minutes after it was rammed by a freighter Sunday night.

Vlasov said 37 more bodies have been recovered, bringing the confirmed death toll to 116. There appeared little hope any of the 282 other people still missing would be found alive.

He said both captains, Vadim Markov of the Admiral Nakhimov and Viktor Tkachenko of the freighter Pyotr Vasyov, ''are now in custody. They've been arrested.''

He said the share of responsibility borne by each captain had not yet been determined.

The cruise ship, packed with 1,234 Soviet tourists and crew, was rammed by the freighter late Sunday night about 9 miles from the port of Novorossiysk and 2 miles from shore. The freighter did not sink, and no one on it was hurt.

Vlasov said both ships were traveling at about 10 knots per hour, or 11 1/2 mph.

The Communist Party daily Pravda said specialists already have determined the crash was caused by ''violation by captains of both ships of rules of safe navigation.''

Two other official newspapers said the accident resulted from ''slovenliness and carelessness.''

More than 400 people have been questioned by an investigatory commission, said the government newspaper Izvestia. It said ''those by whose guilt the accident occurred'' will be tried, but did not give any names.

''After the investigation, we will submit the case to a court of justice, and the court will mete out punishment,'' Vlasov said.

The ships' captains are the only people reported under arrest.

Vlasov said the search for the missing continued Thursday even though no survivors have been found since 836 people were rescued Sunday and Monday.

Vlasov said divers surveyed the wreck Monday and banged on the hull to see if any passengers were trapped in air pockets inside the vessel. But he said they found no signs of life.

Izvestia said one of the divers, identified as Y. Smaga, photographed the ship lying on its side in 155 feet of water and looked into some passengers' cabins through the portholes.

Izvestia said the collision was marked by ''obvious negligence'' and said this was illustrated by the fact that investigators still were unable to compile a list of people aboard the cruise ship.

Vlasov, however, said a full list of the 888 passengers and 346 crew members has been drafted.

Igor Averin, spokesman for the Merchant Marine Ministry, has said the crews of the two ships were talking by radio about how to steer apart when the collision occurred.

Vlasov confirmed there also was ''a communication between the captain of the ship Admiral Nakhimov and an onshore facility,'' which he did not identify. Investigators are still uncertain about what was said, according to Vlasov.

The government has set up a financial aid program for the families of those who died and also is giving medical and material help to the survivors, Vlasov said.