Herbert Smith and Linklaters have advised on a $2bn (£1.3bn) oil exploration financing agreement between Russian oil giant Rosneft and Italian energy company Eni.

Herbert Smith led for Eni with a team including Moscow corporate partner Danila Logofet and finance partner Ed Baring, while Linklaters acted for Rosneft with Moscow corporate partner Grigory Gadzhiev and Moscow managing partner Matthew Keats in the lead.

The deal has seen Eni agree to finance up to $2bn of exploration costs for Rosneft across three offshore fields in the Barents and Black Seas, with excess costs split between the two companies.

The move comes after Rosneft sealed several joint venture agreements in June this year with Eni and Norway's Statoil in a bid to share exploration costs to investigate new sites.

The deal was signed earlier this month at a meeting between Russian Prime Minister Dmitry Medvedev (pictured) and his Italian counterpart Mario Monti.

Logofet commented: "The Barents Sea is a major new oil and gas province and we are delighted to have advised Eni on this landmark and strategically important deal."

The news comes after Herbert Smith and Allen & Overy both advised on a multibillion-dollar financing facility for Rosneft at the close of last year to create a multi-currency facility to raise capital for exploration.