BEIJING - A senior Chinese diplomat here on Thursday expressed his optimism that China and Russia will strike deals on natural gas cooperation ahead of the next prime ministers' regular meeting in autumn.

Assistant Foreign Minister Cheng Guoping said he was upbeat on the Sino-Russian energy cooperation, while replying to a question at a press briefing on the 10th anniversary of the signing of the China-Russia Treaty of Good-Neighborliness, Friendship and Cooperation.

As long as both sides can discuss on the principle of mutual understanding, mutual accommodation and mutual benefit while meeting each other half way, and sincerely implement the common consensus reached by the two state leaders, the deal on natural gas cooperation can be clinched ahead of Russian Prime Minister Vladimir Putin's visit to China, which is slated for the fourth quarter of this year, Cheng said.

In 2009, Russia inked a framework agreement with China on annually supplying at most 70 billion cubic meters of natural gas to China, but both sides have not reached an agreement on the price of the gas.

These projects on natural gas consist of "west line" and the "east line," both of which are 30-year deals.

As these are long-term and major projects, the companies of the two countries need more time to nail down every detail, including the gas pricing, Cheng said.

During Vice Premier Wang Qishan's visit to Russia in June, China and Russia inked a protocol to a gas cooperation memorandum of understanding. Cheng said the protocol outlined the consensus on the principle and pace of the negotiations on the "west line."

The two companies will continue negotiations on the "west line" project, Cheng said, adding he believes the two sides can reach a final solution acceptable to both.

Premier Wen Jiabao held the 15th regular meeting with his Russian counterpart last November, during which he voiced the hope to deepen bilateral cooperation in gas and oil.

Energy cooperation constituted a major part of Sino-Russian ties, Cheng said.

By the end of June, Russia had pumped 7.5 million tonnes of oil to China through the Sino-Russian oil pipeline project, which was put into operation on January 1, Cheng said.

He also voiced the willingness to enhance Sino-Russian cooperation on nuclear safety.

Speaking highly of the bilateral relationship, Cheng said the ties achieved leap-forward development since the signing of the China-Russia Treaty of Good-Neighborliness, Friendship and Cooperation. The treaty was signed in Moscow on July 16, 2001.

In 2004, China and Russia inked an additional treaty over their eastern border, putting an end to 40 years of negotiations over their 4,300-km-long border and getting rid of the biggest hindrance to the development of the bilateral relationship.

Economically, two-way trade between China and Russia has increased seven-fold from some 8 billion U.S. dollars in 2000 to nearly 60 billion dollars in 2010.

China and Russia also have enjoyed close cultural exchanges. China hosted the "Year of Russia" in 2006 and "Year of Russian Language" in 2009, while Russia held celebrations marking the "Year of China" in 2007 and "Year of Chinese Language" in 2010.

The two countries will also hold a series of activities to celebrate the reciprocal "Tourism Year" in the next two years.

Cheng also hailed the treaty's active role in facilitating the two countries to closer coordinate on regional and international issues.

China and Russia are members of the Shanghai Cooperation Organization (SCO), which groups China, Russia, Kazakhstan, Kyrgyzstan, Tajikistan and Uzbekistan.

Cheng also stressed that China highly values the responsibility as the rotating president country of the Shanghai Cooperation Organization (SCO).

"China is discussing with other SCO member countries to map out the work plan and agenda for the organization in the coming year," he said.