High altitudes, rugged terrain and limited logistics support in quake-hit Yushu prefecture of Northwest China's Qinghai province have made rescue and relief work difficult, an official said on Thursday.

Many rescuers and trained dogs working in the quake zone were suffering from altitude sickness, Miao Chonggang, deputy director of China Earthquake Administration's quake relief and emergency response department, said at a press conference in Beijing.

Yushu prefecture sits about 4,000 meters above sea level.

The second difficulty is the complicated geographic conditions in Yushu, which pose a obstacle to transportation for rescue workers, Miao said.

It is about 800 km from the provincial capital of Xining to Yushu, which takes at least 12 hours by car.

The third problem, Miao said, is that logistical supplies at the locale are very limited, adding that rescue teams have to rely on themselves to survive.

Temperatures in Yushu vary from around 10 C in the day to minus 5 C at night.

The weather makes rescue work difficult, and high altitude and the cold also pose dangers to the victims.

Cai Zhengdong, director of the Shanghai Trauma First Aid Center, said that in cold weather with less oxygen, the blood vessels of injured people may constrict, causing the injured body part to die. Furthermore, patients' kidneys will start failing, he said.

Cai said the dusty wind in Yushu also impedes the recovery of surgical patients.

Cai, who had taken part in the relief work in Southwest China's Sichuan province after the 8 magnitude quake in 2008, stressed that the first 72 hours after the quake are "exceedingly important" to rescue trapped people.

"The situation in Yushu is quite different from that in Wenchuan, Sichuan. Wounded people are very likely to stop breathing in an oxygen-poor and cold environment," he said.

Zheng Guoguang, director of China Meteorological Administration, required relevant local departments to give careful and practical weather forecasts in the quake-hit areas, including fire warnings in the densely constructed tent areas.

Zhang Guosheng, deputy director of Qinghai meteorological bureau, said weather departments are paying close attention to changes in the weather, and weather information would be reported to disaster relief headquarters hourly.

Meanwhile, experts and professionals have been dispatched to analyze recent climate related materials.

Zhang said a work team was rushing to repair equipment in Yushu to ensure a smooth weather forecast service.