MOSCOW - The sunken submarine Kursk has a ''terrifying hole'' on its starboard side, a top Russian official said Thursday as new underwater film indicated that an explosion wrecked the vessel and sent it plunging to the sea bottom in seconds.
Deputy Prime Minister Ilya Klebanov said most of the nuclear submarine's 118 crewmen were likely in the damaged section of the vessel, suggesting they had no time to escape.
A Russian rescue effort has failed to reach the sub, which is trapped 354 feet down in the Barents Sea. Rescue teams from Britain and Norway cannot get to the site until the weekend.
Russian theories about what befell the vessel on Saturday range from the explosion to a collision with a ship to contact with a World War II mine.
The Russian navy said the new film of the stricken sub suggested that an explosion had hit the Kursk and that the vessel is sinking into the mud of the sea bottom.
Klebanov said experts reviewing days of rescue efforts to save the Kursk believe the submarine hit ''a huge, heavy object.''
''A rather big part of the crew was in the part of the boat that was hit by the catastrophe that developed at lightning speed,'' Klebanov told reporters in Murmansk, home of the Russian Northern Fleet.
The film showed enormous damage to the forward half of the submarine that would have sent the vessel to the bottom in seconds, navy officials said. The control room where most of the crewmen work is below the conning tower, suggesting many sailors would have had no time to escape when the submarine went down.
U.S. officials speaking on condition of anonymity said American submarines monitoring Russian navy exercises when the Kursk went down detected two explosions at the time. The second explosion was much larger than the first, the officials said.
For loved ones of the missing crewmen, the wait is brutal. With little reliable information, people trade thirdhand reports and listen desperately - and religiously - to the radio, hoping for anything that will give them hope. But they have terrifying ideas about conditions below the water.
''They are cold now, and have no lights,'' said Vyacheslav Olnev, a Murmansk factory worker who served on a submarine.
Murmansk's St. Nicholas church has held special services to pray for the crew. Worshippers light candles in front of icons.
Ludmila Milyutina, whose son Andrei is aboard the Kursk, said that when she called a government hot line for information on the disaster, she was told ''Go to Murmansk and ask journalists.''
Russian rescuers continued their agonized efforts Thursday to reach the crew, whose status is unclear. Russian officials have repeatedly given contradictory reports of whether rescuers had detected any signs of life from within the Kursk.
High-tech foreign teams whose help was requested only a day before began a painfully slow trip that won't get them to the disaster scene before the weekend.
Russian Navy deputy chief Adm. Alexander Poboi said there could be enough air aboard the Kursk for the crew to survive two to three weeks. But oxygen equipment could have been destroyed or damaged and Klebanov said ''there have been no sounds for quite a long time'' from inside the Kursk.
And in another somber assessment, Prime Minister Mikhail Kasyanov said the situation was ''close to catastrophic.''
Rescue capsules have been trying for the past three days to link up with the submarine, but were again driven back again Thursday by racing currents and swirling sand in the inky darkness.
Interfax news agency quoted navy spokesman Capt. Igor Dygalo as saying the ship's sinking into the mud ''does not significantly impact the rescue operation.'' The submarine is leaning at a sharp angle, which also impedes rescue work.
After resisting Western offers of assistance for days, Russia on Wednesday turned to Norway and Britain. But it took almost a full day after that for a Norwegian ship carrying a British rescue mini-submarine to set sail and it was not expected to arrive until late Saturday. A second ship carrying Norwegian divers was expected to arrive Sunday.
The Pentagon said Thursday that Russia has not responded to Defense Secretary William Cohen's offer to provide U.S. military assistance to the Kursk. Cohen made the offer in a letter delivered Tuesday, and President Clinton repeated it in a telephone call the next day with Russian President Vladimir Putin.
The Russian navy refused to confirm the reports from U.S. officials about two explosions. Officers did say, however, that a single explosion in the torpedo compartment at the front of the submarine apparently caused the Kursk to sink. A likely scenario was that one torpedo exploded, setting off a much bigger explosion of other torpedoes.
The Kursk can carry up to 28 torpedoes and anti-submarine missiles, each with warheads weighing up to 1,000 pounds. An explosion involving even a few torpedoes would have caused catastrophic damage, officers said.
Russian officials have said the Kursk carried no nuclear weapons.
Russia's slow, confused and often-contradictory response to the disaster has brought a wave of criticism at home. The accident was not announced until two days after it happened and relatives of crew members learned of the sinking not from the military but from television.