Staff members load rescue materials onto a helicopter in Xinjiang, where at least seven people were killed and more than 400 others were trapped by two avalanches on Thursday, February 25, 2010. [Xinhua]

Two helicopters were sent Friday morning to rescue the hundreds of people who were trapped by two deadly avalanches in northwest China's Xinjiang Uygur Autonomous Region, the emergency rescue headquarters said.

A spokesman for the headquarters said the helicopters took off at 10:30 AM, with missions to air drop food, medicine, equipment of communications and to rescue the 129 trapped in Kazak Autonomous Prefecture of Ili, including 29 reported to have been trapped in an iron mine in Nilka county.

Helicopters will also fly to the nearby Hejing County of Bayingolin Mongolian Autonomous Prefecture to rescue 276 herders trapped there.

"Children, senior citizens and women will be placed up in our rescue missions, but the exact number of the three groups being trapped remains unknown," said Ili Ismail, vice director of the general office of the Xinjiang Autonomous Regional Government.

The official, who is also commander-in-chief for on-site rescue operation, said apart from saving as many as possible the avalanche-trapped victims by helicopter, air dropping plenty of food, medicine, equipment of communication if conditions won't allow transport of the trapped residents by copter, the rescuers would do aerial surveillance to provide information for decision-making in carrying out rescue operation on the ground.

The recent two avalanches in Xinjiang have killed at least seven people and trapped more than 400 others as rescuers found more people being caught in snow Thursday.

The rescue headquarters Thursday sent a helicopter that reached a coal mine in a small valley 20 km from the avalanche in Ili Kazak, where more than 100 workers were trapped. The aircraft, which could not locate a landing spot, left after dropping some food and a satellite phone

According to an official from the county's work safety department, a 3.7-magnitude earthquake struck Nilka county at around 5:51 PM Tuesday.

The seven people found dead in the avalanches included two herdsman in Bayingolin's Hejing County, two children in Ili Kazak's Xinyuan County and one iron ore miner and his wife and daughter.

The iron mine called Songhu produces 1 million tonnes of iron ores annually. It is adjacent to the Hejing county's Kunes township in Bayingolin.

Xinjiang has been experiencing the heaviest snow and coldest temperatures in decades this winter. The public has been warned that due to large amount of accumulated snow, the warmer temperatures in spring may bring severe floods and avalanches to the region.