Allen & Overy (A&O) and Curtis Mallet-Prevost Colt & Mosle have advised on the $1.6bn (£1bn) acquisition of a 50% stake in a German refinery by Russian oil company Rosneft.

Rosneft has acquired the stake in Ruhr Oel from Venezuelan oil company Petroleos de Venezuela (PdVSA). Ruhr Oel was previously a 50/50 joint venture between BP and PdVSA.

A&O advised Rosneft, fielding a team led by corporate partner Tim Shilling alongside corporate partner James Roe.

New York-based firm Curtis advised PdVSA with corporate partners Guillermo Ulke and Thilo Winkeler acting on the deal.

Shilling said: "This is a strategic deal that allows Rosneft to expand its presence in one of its key international markets.

"There have been signs of a trend by Russian majors with access to funds to look to invest outside of Russia. Over the past year a number of these Russian investors have been looking to invest abroad. Current indications are that the Russian M&A market is picking up and that there will also be more inbound investment."

Barclays Capital acted as the financial adviser for Rosneft.

The agreement was signed last Friday (15 October) in a ceremony at the Kremlin attended by Russian President Dmitry Medvedev and Venezuelan President Hugo Chavez.

The deal follows a number of outbound investments by Russian companies with Russian telecoms operator VimpelCom set to acquire Weather Investments next year in a $21.5bn (£13.6bn) tie-up announced earlier this month.