Moscow, Feb 9 (IANS/RIA Novosti) Russian scientists are planning to use robotic probes to reach water layers at the bottom of an ancient sub-glacial lake in Antarctica in 2013-2014.

The St. Petersburg Arctic and Antarctic Research Institute Wednesday confirmed that Russians reached the surface of Lake Vostok, the largest of nearly 400 sub-glacial lakes on the continent, and stopped drilling at the depth of 3,768 meters (12,366 feet).

The water, which rushed 30-40 meters up under pressure following the breach of the ice cover, froze at the lower part of the bore hole. Russian researchers will extract the frozen drill sample at the start of the next research season in December 2012.

"The drill sample from Lake Vostok will be delivered on board the Academician Fedorov ship to St. Petersburg in May 2013," Russian astrobiologist Sergei Bulat said. "Only then it will become available for study."

Bulat said, though, that the sample from the surface may not prove the existence of biological forms in the ancient lake and only the search at the bottom would bring definitive results.

"We cannot rely on this sample alone to claim the existence [or non-existence] of life in the lake," the scientist said. "The surface layers may be too cold for any bacteria to survive."

According to Bulat, several robotic probes are being developed in the St. Petersburg Institute of Nuclear Physics to help researchers explore the bottom layers of the lake during the 2013-2014 season.

Russian scientists hope the study of Lake Vostok could reveal new forms of life and show how life evolved before the ice age.

The exploration of the lake may also help with the search for life under the ice crust on Mars and Jupiter's moon Europa.