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A group of Russian scientists plumbing the frozen Antarctic in search of a lake buried in ice for tens of millions of years have failed to respond to increasingly anxious U.S. colleagues -- and as the days creep by, the fate of the team remains unknown.

"No word from the ice for 5 days," Dr. John Priscu professor of Ecology at Montana State University, told FoxNews.com via email.

The team from Russia's Arctic and Antarctic Research Institute (AARI) have been drilling for weeks in an effort to reach isolated Lake Vostok, a vast, dark body of water hidden 13,000 ft.  below the ice sheet's surface. The lake hasn't been exposed to air in more than 20 million years.

Priscu said there was no way to get in touch with the team -- and the already cold weather is set to plunge, as Antarctica's summer season ends and winter sets in.

"Temps are dropping below -40 Celsius [-40 degrees Fahrenheit] and they have only a week or so left before they have to winterize the station," he said. "I can only imagine what things must be like at Vostok Station this week."

The team's disappearance could not come at a worse time: They are about 40 feet from their goal of reaching the body of water, Priscu explained, a goal that the team was unable to meet as they raced the coming winter exactly one year ago.

When the winter arrives in the next few weeks, the temperature can get twice as freezing. Vostok Station boasts the lowest recorded temperature on Earth: -89.4 degrees Celsius (-129 degrees Fahrenheit).

If the team does reach the lake water, they will bring its water up through the hole and let it freeze there over the winter. The following year they will be able to start research on what they find, Priscu explained.

While there are only a few researchers actually working at the lake, scientists around the globe have been waiting with baited breath to see what the Russian's unearth this weekend.

"We are terribly interested in what they find," Alan Rodger, a scientist at the British Antarctic Survey, told FoxNews.com last year. "This is a lake that we don't think has been exposed for 15 million years. Therefore, if there is life there, we're going to have so many questions. How has it evolved over those years, how has it survived, what does it look like? Won't it be exciting to find something completely new on Planet Earth?"

Hey, where's the lake? Hidden beneath nearly 2 miles of ice in Western Antarctica.

The Lake Vostok project has been years in the making, with initial drilling at the massive lake -- 15,690 square kilometers (6,060 sq mi) -- starting in 1998. Initially, they were able to reach 3,600 meters, but had to stop due to concerns of possible contamination of the never-before-touched lake water.

"Ice isn't like rock, it's capable of movement," Dr. Priscu told FoxNews.com. "So in order to keep the hole from squeezing shut, they put a fluid in the drill called kerosene. Kerosene also grows bacteria, and there's about 65 tons of kerosene in that hole. It would be a disaster if that kerosene contaminated this pristine lake."

But the scientists came up with a clever way to make sure this debacle would not occur. They agreed to drill until a sensor warned them of free water. At that point they will take out the right amount of kerosene and adjust the pressure so that none of the liquids fall into the lake, but rather lake water would rise through the hole.

Priscu was concerned for his colleagues, but also admits the stunning scope of the story.

"It could be fodder for a great made-for-TV movie," he said.

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