With experience from relief operations in southwest Sichuan nearly two years ago, the Chinese armed forces have been immediately called upon in the wake of the 7.1-magnitude quake that struck high-altitude Qinghai Province on Wednesday.

The People's Liberation Army (PLA) Air Force was the first to respond to the emergency rescue operation deployed by the Central Military Commission (CMC) Wednesday.

Some 10 Russian-made Il-76 carrier aircraft - the largest airlifter the PLA has - had transported nearly 100 tonnes of relief goods and hundreds of rescuers to the epicenter within 32 hours of the devastating quake.

To maintain a smooth coordination around the clock at the only airport in the quake zone, the Air Force also deployed additional radar, illumination and navigation devices to Yushu airport for safe nighttime operations.

The PLA Navy, though the quake-hit Yushu Tibetan Autonomous Prefecture is thousands of miles away from the coast line, has deployed a remote sensoring aircraft to fly over the epicenter to collect real-time geological information which may help save survivors.

The navy's remote sensoring aircraft has also provided navigation assistance to other aircraft flying in and out Yushu airport, as ground signalling in the quake zone has been affected.

The PLA's Second Artillery Corps, the troops responsible for China's nuclear deterrent who seldom expose themselves to the outside world, were also mobilized.

An advanced contingent from the Second Artillery Corps set off on the night after the quake and arrived in Yushu Thursday afternoon. They have brought field operation vehicles, hoisting machines and other heavy equipment which could help dig people out from under the quake debris.

PLA ground troops from major military commands in Lanzhou, Jinan and Chengdu, which surround the Qinghai Province, were rushed to the quake zone on the 4,000-meter-high Qinghai-Tibetan Plateau.

Some 3,450 light-packed troops from the People's Armed Police Force (PAPF) entered the quake-hit zone and repaired a road to connect the affected area to the outside.

More than 10,000 uniformed troops with the PLA and the PAPF had been mobilized to answer the emergency order from CMC Chairman Hu Jintao, commander-in-chief of the nation's armed forces.

In a mandate issued by the PLA's General Staff Headquarters and the General Political Department, the CMC ordered the troops mobilized for relief operations to "spare no effort and save every second" to arrive at the quake zone.

The headquarters ordered troops already in the quake zone to make saving survivors the top priority and cooperate with civilian quake-relief personnel.

The high altitude of the Qinghai quake zone has been a major obstacle for rescuers who come from regions of much lower altitude. Many soldiers, and even sniffer dogs, have displayed signs of altitude sickness.

General Li Suzhi, a veteran plateau doctor with the PLA's Tibetan Military Sub-command, has suggested all rescuers in the quake zone keep warm. He has also provided a practical field manual for work in high-altitude regions.