A military transport helicopter engaging in quake relief work near the Yingxiu Township, Wenchuan County in Southwest China's Sichuan Province crashed on Saturday afternoon, according to military sources.

A crew of five and 14 injured local residents were on board for transfer when the Mi-171 helicopter with the quake relief troops of the Chengdu Military Area Command crashed at 2:56 p.m., the military sources said.

The helicopter was returning from a mission to carry epidemic prevention experts to Lixian County when it encountered strong turbulence and fog and crashed.

Chinese President Hu Jintao, also General Secretary of the Communist Party of China Central Committee and Chairman of the Central Military Commission, has instructed local authorities to carry out search and rescue operations immediately.

Hu, who is overseeing quake relief operations in Hanzhong, Shaanxi Province, has also instructed vice chairman of the Central Military Commission Guo Boxiong to fly to front line to direct relevant operations.

Guo is en route to Sichuan, and the Chengdu Military Area Command is already carrying out search and rescue operations.

By 7:00 p.m. Sunday, the helicopter was still missing and no person on the helicopter had been found.

By Sunday mid-night, two rescue helicopters had launched five rounds of search while the land troops had been continuously hunting for more than 30 hours. The military is broadening the searching scope.

Since the crashing site was among the canyons surrounded by high mountains, the mission was really arduous, the military sources said.

More than 2,500 soldiers were sent to the site for the search and rescue operations.

The five-member crew, led by Qiu Guanghua, has completed 63 flights, transferring 25.8 tons of relief materials, 87 quake relief workers and 234 victims since the May 12 quake jolted southwest China's Sichuan province.

Qiu's crew had always been excellent in completing military missions and this time the task was very tough. The accident occurred among very complicated terrain while the weather was unpredictably abominable, said sources with the Chengdu Military Command Area.

Editor: Yan