The China Earthquake Administration, the Red Cross Society of China, and authorities in the neighboring Gansu, Sichuan provinces and Tibet Autonomous Region, as well as Beijing, have also dispatched rescuers to Yushu.
Tents, cotton-padded clothes and quilts are being rushed to the region from various parts of the country.
"Our top priority is to save students. Schools are always places that have many people," said Kang Zifu, an army officer in the rescue operation in Gyegu.
The quake also killed five people and injured one in the Shiqu County, which neighbors Yushu, in the Tibetan Autonomous Prefecture of Garze in Sichuan Province, local authorities said.
Lying on the Qinghai-Tibet Plateau, Yushu has an altitude of above 4,000 meters.
The Qinghai Provincial Observatory forecast Wednesday that Yushu would see strong winds and sleet in the coming days, which would hamper rescue efforts.
CASUALTIES, DAMAGES AND LOSSES
Samdrup Gyatso, 17, who ran a shop in his two-story house in Gyegu, lost his relatives in the earthquake.
"There are 10 people in my family and only four of us escaped. One of my relatives died. All the others are buried under the rubble," he said.
Many local residents were seen Wednesday afternoon taking cars, mini-vans and tractors to flee the town.
Three tents have been set up in the government compound of the Yushu prefecture, which accommodated about 60 people.
More than 85 percent of the houses in Gyegu had collapsed, said Zhuohuaxia, a publicity official with the Tibetan Autonomous Prefecture of Yushu.
"The streets in Gyegu are thronged with panic, injured people, with many bleeding from the head," he said.
"Many students are buried under the debris due to building collapse at a vocational school," he said.
"A large crack appears in the wall of the Yushu Hotel, and part of a government office building also collapsed," he said.