Russia will supply about 70 percent of oil at market prices for a proposed joint refinery between Rosneft and China National Petroleum Corp (CNPC), Reuters said Thursday, citing a Russian news agency.

The two companies signed an initial deal for the multi-billion-dollar Tianjin refinery more than four years ago, Reuters said.

CNPC, parent of PetroChina, will hold a 51 percent stake in the joint refinery, which is supposed to have an annual refining capacity of 15 million tons, while Rosneft, a leading company of the Russian petroleum industry, will take the remaining 49 percent, Zhang Guobao, China's energy chief, was quoted as saying by a Russian news agency, sinopecnews.com.cn reported.

The other 30 percent of oil for the refinery will be delivered from Asia, Zhang said, according to Reuters.