China National Offshore Oil Company Limited (CNOOC), the country's largest offshore oil and gas producer, has signed an agreement on exploiting energy resources with China Ocean Shipping (Group) Company (COSCO Group), China's largest shipping group.

The two sides have agreed to jointly exploit energy resources including liquid natural gas (LNG) by transferring CNOOC shares to COSCO Group or co-funding, CNOOC, the country's third-biggest oil company has said in an announcement on its website.

The two companies will also cooperate on shipbuilding, according to the announcement.

CNOOC and COSCO have been cooperating on transportation of crude oil, oil products, LNG, natural gas pipes and other facilities.

"We are complementary to COSCO in business and prospects for mutual cooperation are promising," said Fu Chengyu, chairman and chief executive officer of CNOOC.

CNOOC has reported first half net profits down by 10.6 percent from the same period last year to 14.55 billion yuan.

COSCO Group is China's largest ship repair and marine engineering and shipping group and one of the top shipping conglomerates in the world.