It was unclear whether there was enough oxygen aboard the mini-sub to keep the crew alive long enough for remote-controlled vehicles to reach them from bases in San Diego and Britain.
A Russian rescue vessel hooked a cable onto the mini-submarine and was towing it to shallower waters, the commander of the Pacific Fleet was quoted as saying later Friday.
Admiral Viktor Fyodorov said the rescue vessel was trying to raise the stranded vessel as it was being towed, the Interfax news agency reported.
However, the agency later cited the deputy head of the naval general staff, Vladimir Pepelayev, as saying it was premature to say the mini-sub had been hooked.
Navy spokesman Capt. Igor Dygalo told The Associated Press that tension was noted on a cable being used in the attempt to hook the submarine, but it could not be confirmed that the vessel had been snagged.
Interfax earlier quoted Fyodorov as saying the crew's air supply would last until sometime Monday. However, he earlier told Russia's Channel One television that air would last "a little more than 24 hours."
The Russian sub's propeller became entangled in a fishing net Thursday, Dygalo said on state-run Rossiya television. The accident occurred in Beryozovaya Bay, about 50 miles south of amchatka's
"There is air remaining on the underwater apparatus for a day - one day," Dygalo said at about 6 a.m. EDT. "The operation continues. We have a day, and intensive, active measures will be taken to rescue the AS-28 vessel and the people aboard."
Fleet spokesman Capt. Alexander Kosolapov said contact had been made with the sailors, who were not hurt.
The mini-sub, called an AS-28, initially was too deep to allow the sailors to swim to the surface on their own or divers to reach it, officials said. However, dragging the sub into shallower waters could make such an escape or rescue possible.
The crisis evoked comparisons with the 2000 disaster involving the nuclear submarine Kursk. The Kursk sank to the bottom of the Barents Sea after explosions on board, killing all 118 seamen aboard.
However, some Kursk sailors survived for hours as oxygen ran out, and President Vladimir Putin was criticized severely for waiting several days before asking for international assistance.
Also, Russian divers discharged by the navy for lack of funds said at the time their own offers to help were rebuffed.
Both accidents raised questions about the state of Russia's cash-strapped military. The same type of vessel that is now stuck, called a Priz, was used in the rescue efforts that followed the Kursk disaster, Interfax reported.
The latest accident occurred early Thursday after the mini-submarine was launched from a rescue ship during a combat training exercise, Kosolapov said. The AS-28, built in 1989, is about 44 feet long and 19 feet high and can dive to depths of 1,640 feet.
Russia appealed to the United States and Japan for assistance, the Interfax news agency quoted Foreign Ministry spokesman Boris Malakhov as saying.
The U.S. Navy was loading two robotic rescue vehicles aboard a massive C-5 transport plane at Naval Air Station North Island near San Diego for the flight to Russia. The loading was expected to take about two hours, officials said.
The unmanned vehicle, called a Super Scorpio, can reach depths of up to 5,000 feet and is equipped with high-powered lights, sonar and video cameras, said Capt. Matt Brown, a spokesman for the U.S. Navy's Pacific Fleet in Honolulu.
The Deep Submergence Unit team is scheduled to depart at 1:45 p.m. EDT, the Pentagon said.
on a Russian ship before making its descent to the stricken vessel.
Brown said the Russian military has indicated that the AS-28 may have been fouled by fishing nets or steel cables. The Super Scorpio has an instrument that can cut 1-inch-thick steel cables, he said.
The Super Scorpio, which weighs about 4,500 pounds, has been used to conduct underwater surveys and inspections.
About 30 people will accompany the vehicle to Russia, Brown said.
"We are working as fast as we can to make this happen," he said.
The British vehicle was being loaded onto a Royal Air Force transport plane at Scotland's Prestwick airport and was expected to arrive at Petropavlovsk-Kamchatsky, the city nearest the site, at about 5 a.m. Saturday, said Anton Atrashkin, spokesman for the British Embassy in Moscow.
That means the British vessel likely will arrive before the U.S. vessel.
Since Soviet times, the Kamchatka Peninsula has housed several major submarine bases and numerous other military facilities, and large areas of it have remained closed to outsiders.
Airlifting a U.S. underwater vehicle to the area will mark the first time since the World War II era that a U.S. military plane has been allowed to fly there.
At Moscow's request, Japan dispatched a vessel carrying submarine rescue gear and three other ships to join salvage efforts, but they were not expected to arrive at the scene until early next week, Marine Self Defense Force spokesman Hidetsubu Iwamasa said.
Since the Soviet collapse, the Russian navy has struggled to find funds to maintain and repair its ships and has had to scale back its modernization program.