May 19 (Bloomberg) -- Korea Gas Corp., the world's biggest buyer of liquefied natural gas, and Gazprom OAO, the biggest natural-gas producer, agreed to extend a cooperation agreement until 2013 to secure a stable supply of the fuel.

The companies will continue to cooperate in jointly developing gas projects in Russia and building a LNG plant and a gas chemical complex, Korea Gas said in a statement today.

Asia's fourth-largest economy, which imports 97 percent of its energy needs, wants to diversify its supplies amid surging energy prices and intensifying competition from China and India.

Under the deal, Korea Gas is seeking to import 1.5 million metric tons of gas a year from Gazprom's Sakhalin-2 project. Sakhalin-2, which had originally planned to export its first LNG cargo in the second half of this year, delayed the shipment until 2009, Royal Dutch Shell Plc, which owns 27.5 percent of the venture, said on April 29. Gazprom owns 50 percent plus one share, Mitsui & Co. holds 12.5 percent and Mitsubishi Corp. has 10 percent.

The 2003 agreement between the companies was initially scheduled to expire at the end of this month.