Russian state oil major Rosneft and American energy giant ExxonMobil have set up a tender for the design and construction of oil rigs that would facilitate their exploration of the Arctic shelf, Rosneft said in a statement.

The move is the latest development in the strategic cooperation between the two energy behemoths, which signed an agreement last April to develop offshore hydrocarbon deposits in the Kara and Black seas. The two companies estimate that in the Kara Sea alone, there is a deposit of around 85 billion barrels of oil, scattered throughout some 23 different areas.

Drilling is expected to start in 2015.

The Arctic has become the latest hotspot for energy development, as countries with an Arctic border have raced to the region to develop energy deposits. But exploration is technically challenging, and energy giants have been scrambling for the latest and most advanced technology to properly tap the deposits.