SHENYANG, China - Rescue crews were searching today for coal miners missing nearly 800 feet underground after a gas explosion in China's northeast killed 203 people in the deadliest mining disaster reported since communist rule began in 1949.

The explosion Monday afternoon at the Sunjiawan mine left 13 miners trapped underground and injured 22, the official Xinhua News Agency reported.

The cause of the blast was under investigation, Xinhua said. It said the disaster occurred 794 feet below the surface of the mine.

President Hu Jintao and other Chinese leaders issued orders for local officials "to spare no effort to rescue those stranded in the mine," Xinhua said. It said they called for "strict measures" to prevent any more such disasters.

China has suffered a string of deadly mining disasters in recent months despite a nationwide safety campaign.

A blast in the northern province of Shaanxi in November killed 166 miners. Another explosion in October killed 148. Before that, the deadliest reported mining accident in recent years was a fire in southern China that killed 162 miners in 2000.

Monday's disaster was the deadliest reported by the Chinese government since the 1949 communist revolution. However, in 1942, China's northeast was the site of the world's deadliest coal mining disaster when an accident killed 1,549 miners in Japanese-occupied Manchuria during World War II.