A British remote-controlled vehicle on Sunday cut away the cables that had snarled a Russian mini-submarine and its seven-man crew deep under the Pacific Ocean (search), and rescuers were preparing for the sub to surface, a naval spokesman said.

Capt. Igor Dygalo (search) told The Associated Press that the Super Scorpio had freed the mini-sub from the military antenna that had tangled it some 625 feet below the surface.

With oxygen supplies dwindling after nearly three days underwater off the Kamchatka Peninsula (search), rescuers were racing to try and bring the 44-foot-long AS-28 to the surface in Beryozovaya Bay, about 10 miles off Kamchatka's east coast.

But a mechanical problem with the Super Scorpio forced workers to bring the rescue vehicle to the surface, delaying a process complicated by the discovery of a fishing net caught on the mini-sub, Interfax quoted another naval spokesman as saying.

"After the last cable holding down the mini-sub was cut off, rescuers found a piece of fishing net on the nose of the submersible," Capt. Alexander Kosolapov was quoted as saying. "They were unable to take it off because the Scorpio had to be raised to the surface due to functioning problems."

Russian ships had earlier managed to loop cables under the antenna that snared the ship on Thursday. It was unclear whether workers intended to raise the sub, or if the vessel would perform an emergency surfacing, rising rapidly to the surface.

Russian authorities have been hoping the British unmanned submersible could help free the sub and avoid losing a sub crew as they did with the Kursk nuclear submarine, which sank almost exactly five years ago, killing all 118 aboard.

Russian estimates of how long the air would last ranged from the end of Saturday until Monday.

A U.S. crew with two other Super Scorpio vehicles was also making its way to the area after landing later on the rain-soaked peninsula. As the American submersibles and crews were being loaded onto ships near the port of Petropavlovsky-Kamchatsky, Cmdr. Bill Hamblet, an assistant U.S. naval attache helping the operation, said the three countries were cooperating with their best equipment and teams.

"It's hard to do anything at that depth, but everyone will try and do their best to save the crew," he told AP.

The Russian navy made contact with the crew late Saturday, and Pacific Fleet commander Adm. Viktor Fyodorov said earlier that their condition was "satisfactory" despite temperatures of 41 to 45 degrees.

In sharp contrast to the August 2000 Kursk disaster, when authorities held off asking for help until hope was nearly exhausted, Russian military officials quickly sought help from U.S. and British authorities.

Officials said the Russian submarine was participating in a combat training exercise and got snarled on an underwater antenna assembly that is part of a coastal monitoring system. The system is anchored with a weight of about 60 metric tons (66 short tons), according to news reports.

Rear Adm. Vladimir Pepelyayev, deputy head of the navy's general staff, had said the air would likely last to the end of the day and possibly through Sunday. Fyodorov gave a similar estimate, but later was quoted by the Interfax news agency as saying there was enough to last until Monday.

Russia's cash-strapped navy apparently lacks rescue vehicles capable of operating at the depth where the sub is stranded, and officials say it is too deep for divers to reach or the crew to swim out on their own. An earlier attempt to drag the vessel to shallower waters failed when cables detached after pulling it some 65 yards.

The new crisis indicated that promises by President Vladimir Putin to improve the navy's equipment apparently have had little effect. He was criticized for his slow response to the Kursk crisis and reluctance to accept foreign assistance.

By early Sunday, Putin had made no public comment on the latest sinking, but Defense Minister Sergei Ivanov flew to Kamchatka and was traveling to the site of the rescue operation.

The new crisis is highly embarrassing for Russia, which will hold an unprecedented joint military exercise with China later this month, including the use of submarines to settle an imaginary conflict in a foreign land. In the exercise, Russia is to field a naval squadron and 17 long-haul aircraft.