Herbert Smith and Allen & Overy (A&O) have both advised on a multi-billion dollar financing facility for Russian oil giant Rosneft.

A Herbert Smith team led by Moscow finance partner Edward Baring has advised Barclays Bank as agent with 12 other leading banks including Bank of America, JP Morgan and Credit Suisse.

A&O has acted for Rosneft with Moscow banking head Stephen Matthews leading for the magic circle firm.

The deal has seen the creation of a multi-currency facility that includes both a dollar and a euro tranche worth $1.4bn (£902m) and €470m (£394.8m) respectively.

Baring said: "This was a fascinating deal which took place against a backdrop of almost unprecedented volatility in both the financial markets and the interbank lending market.

"Although the scarcity of dollars available to European lenders meant that the facility had to be split into euro and dollar tranches, we are very pleased that Rosneft achieved its overall target of raising more than $2bn (£1.3bn), with 13 international banks from all over the world joining the bank syndicate."

The news follows the $3.2bn (£2bn) Arctic exploration deal struck between Rosneft and fellow oil giant ExxonMobil announced in August this year, which will see the two companies invest in exploring and developing the Russian Arctic for untapped oil and gas reserves. On that deal, Freshfields Bruckhaus Deringer advised Rosneft and Skadden Arps Slate Meagher & Flom advised ExxonMobil.

A&O also advised Rosneft on its $1.6bn (£1bn) acquisition of a 50% stake in German refinery Ruhr Oel from Venezuelan oil company Petroleos de Venezuela that closed in May this year.