China and Russia will jointly invest $5 billion into an oil refinery in Tianjin, a sign of further energy cooperation between the two countries, the Tianjin municipal government said on its website Wednesday.

With a planned capacity of 13 million tons annually, the Tianjin oil refinery will be jointly invested by China National Petroleum Corp and Russia's largest oil company, Rosneft. The Russian government owns a 75 percent stake in the company.

According to the deal, Rosneft will have a 49 percent stake in the project and China 51 percent. In addition, 70 percent of the refinery's oil will be provided by Russia. No details were offered on the source of the remaining 30 percent.

"The oil refining project in Tianjin ... is a milestone in the history of China-Russia energy cooperation," said Cheng Guoping, Chinese assistant foreign minister.

"It is another step in developing cooperation between the largest oil companies of our (two) countries," said Rosneft Chief Executive Eduard Khudainatov.

The refinery project, one of the largest in China, will be located in Tianjin's Nangang Industrial Zone. Construction is schedule d for completion by 2012.

Last year, China signed an agreement for 300,000 barrels of Russian oil a day over the next 25 years in exchange for a $25 billion loan.

Last week, the sixth round of China-Russia energy negotiations kicked off in Tianjin and three agreements were inked during the talks, paving the way for the upcoming meeting of the two countries' presidents later this month.

"All-around and deep energy cooperation between the two countries will be of strategic significance," said Chinese Vice Premier Wang Qishan.

"China is ready to work with Russia to enhance and deepen cooperation in the natural gas, oil, nuclear power, electric and coal industries," Wang said.