ONGC in talks to up stake in Russia's Vankor oilfield - document

MOSCOW (Reuters) - ONGC is in talks to increase its stake in Vankor oilfield owned by Russia's top oil producer Rosneft, official documents showed on Thursday.

The documents, signed during Prime Minister Narendra Modi's visit to Moscow, also call for cooperation between Russian and Indian companies in offshore and onshore exploration and production of hydrocarbons in Russia.

(Reporting by Denis Dyomkin; writing by Vladimir Soldatkin; Editing by Dmitry Solovyov)