Russia's top crude producer OAO Rosneft has agreed to cede a share of its oil riches to China, the world's top oil importer, signing a memorandum on Friday for the joint development of East Siberian deposits.

Russia, the world's top oil producer, has previously preferred to sign long-term supply deals with China backed by multi-billion-dollar loans.

The Russian state-owned company said it signed a memorandum with China National Petroleum Corp to tap oil reserves, including Srednebotuobinsk field.