MOSCOW (AP) _ The captains of two ships that collided in the Black Sea, killing up to 400 people, are being held under guard and are accused of violating navigational safety rules, official Soviet news reports said today.

A Communist Party official, meanwhile, said 37 more bodies had been recovered, bringing to 116 the number confirmed dead in the crash about midnight Sunday. Another 282 people are missing and believed dead.

Albert I. Vlasov, first deputy chief of the party propaganda department, released the new figures at a news conference. He said the cruise liner Admiral Nakhimov apparently sank seven or eight minutes after colliding with the freighter Pyotr Vasyev - about twice as fast as earlier thought and too quickly to deploy any lifeboats.

By Monday, rescuers had pulled 836 people from the water. Vlasov said teams still were searching for any survivors but had little hope anyone would be found alive. He said officials had not decided whether to cut open the liner's hull to recover bodies or to raise the ship.

He confirmed reports in the official press that Vadim Markov, captain of the cruise liner, and Viktor Tkachenko, captain of the freighter, were being held pending an investigation into the crash.

The government newspaper Izvestia said a investigatory commission has questioned 400 people so far, and that there will be a trial of those ''by whose guilt the accident occurred.'' It did not specify who would be tried.

Investigators are trying to put together an exact list of passengers and crew members who were aboard the cruise liner at the time of the accident, Izvestia said. Uncertainty about the passenger list was evidence of the ''obvious negligence'' that led to the accident, the newspaper said.

According to initial reports, there were 1,234 people aboard the Admiral Nakhimov when it sank at about midnight Sunday after being rammed by the freighter.

Press accounts today said 27 of those rescued from the sea were hospitalized, some of them with pneumonia, but none was in danger of dying. A maritime official earlier said 29 were hospitalized.

Izvestia said rumors were circulating that some passengers remained alive in air pockets within the sunken ship. But Vlasov said divers did not find any air pockets. Izvestia quoted a diver, Y. Smaga, as saying there were no signs of life.

Press accounts of the disaster were filled with tales of heroism, self- sacrifice and endurance, but also indicated that carelessness might have led to the collision.

''How could it happen?'' said the Communist Party newspaper Pravda. ''Why is it that two ships which were in communication and saw each other's lights could not steer clear?

''Investigating organs will give detailed answers on this after studying the circumstances,'' it said. ''But already specialists state: the reason was violation by captains of both ships of rules of safe navigation.''

Other newspapers were harsher in their criticism.

''One of the reasons for what happened is simple slovenliness and carelessness,'' said the youth daily Komsomolskaya Pravda.

The newspaper Sovietskaya Rossiya said, ''Final conclusions on the reasons for the tragedy and the degree of guilt of some persons will be established by the state commission, but one thing is already clear: among the reasons that led to the tragedy were carelessness and slovenliness.

Izvestia has quoted a helmsman from the Admiral Nakhimov as saying his ship's bridge staff radioed the freighter to change course before the collision. It said that the Pyotr Vasyev reversed engines just before the crash.

Igor M. Averin, spokesman for the Merchant Marine Ministry, has confirmed the two crews talking by radio about how to steer apart when the accident occurred. The ships collided in clear weather with relatively calm seas.

''The water (around the accident site) was covered by a layer of heavy oil and paint that came from who knows where,'' seaman Stanislav Usanov, one of the rescuers, was quoted as telling Sovietskaya Rossiaya.

''People were swimming in this unbelievable stew of liferafts, pieces of rope and all kinds of things that popped up from the steamer,'' he said.

Newspaper accounts singled out several rescuers for heroism. One young seaman named Vladimir Volodin, who was aboard a pilot boat, was credited with saving a woman and her baby.

''He threw himself into the waves, taking a lifejacket with him, grabbed the woman, took the child in his arms and towed them back to the boat,'' said Volodin's commander, Vladimir Belovol.