File photo of Russian mini-submarine similar to sub trapped under Pacific Ocean

A Russian navy officer says rescuers are hours away from reaching seven Russian sailors trapped aboard a small submarine on the Pacific Ocean floor with a dwindling air supply.

But Rear Admiral Vladimir Pepelyayev says there is enough air on the sub to perhaps last through Sunday.

He says the crew is in "satisfactory condition." 

VOA's Anya Ardayeva reports from Moscow the Russian navy says it managed to contact the crew onboard the AS-28 overnight, and the crewmen were in "satisfactory condition."  The sailors had reportedly locked themselves in one of two sections of the mini-sub to save air and energy.  The temperature onboard the sub is reported to be around 5 degrees Celsius.

U.S. and British planes carrying robotic undersea vehicles have now landed in the region and are to be taken by Russian ship to the site of the rescue effort.  It is hoped the robotic vehicles can be used to investigate the mini-subs condition and if possible use powerful cutting tools to sever whatever cables or nets the sub became entangled in.

While they await the arrival of the U.S. robotic vehicles, Russian Navy rescuers have been working without success to try to tow the ship toward shallow waters.

Vice Admiral Pepelyaev, Deputy Director of Moscow Navy Headquarters says that although Navy officials still don't rule out trying to drag the submarine to shallow waters if it becomes necessary, there are a number of options being looked at. The main option, he said, was to raise the vessel to the surface.

It is now believed the sub is caught up in an underwater antenna assembly that is part of Russia's coastal defenses.  The vehicle was taking part in a training exercise when it was first trapped in what was believed to be a fishing net.

The incident is being compared to the Kursk nuclear submarine disaster five years ago.  All 118 men on board the vessel, which sank in the Barents Sea, died after a failed rescue.

Russian President Vladimir Putin was fiercely criticized for the way Russian authorities handled the disaster and for their refusal to ask for foreign help promptly.  Analysts in Moscow say that this time, the Russian officials were quick to ask other countries for help.