Premier Li Keqiang flew to one of the areas of Sichuan hardest hit by yesterday's earthquake.
The premier ordered rescuers, the military and local-government officials to work together and make the most of the critical first 24 hours following such a disaster to save lives.
Li took a PLA Air Force helicopter to the quake epicentre of Lushan county in Yaan city after arriving in the provincial capital, Chengdu , in the afternoon.
He called a meeting at about 6pm at the frontline headquarters in Longmen township, Lushan.
"Life is the most important thing and the top priority is saving lives," said Li.
The premier was accompanied by Vice-Premier Wang Yang and Yang Jing , the secretary general of the State Council. Li said there should be not be a delay of a minute or even a second during the "golden 24 hours" for saving lives.
"We should also make every effort to prevent any additional casualties from happening during the aftershocks," he said.
"All victims should be properly and safely settled down and have enough food and clean water."
Li said the central government had launched the first emergency response to the earthquake, but urged the rescuers and military to listen to the Sichuan government.
"The provincial government should take the chief commanding role in the disaster relief work, as it is fully supported by the central government and all related ministries," he said. "The army [PLA Air Force and People's Armed Police] should also try their best to meet the requirements of local governments."
Li's actions stood in contrast to those of his predecessor Wen Jiabao , who flew to Sichuan a few hours after the much more devastating earthquake there five years ago. Wen made a tearful call to the air force to send helicopters to save lives. But he received no response because the People's Liberation Army takes its orders only from the Central Military Commission chairman. The premier has no military rank.
China Central Television said Li was endorsed by President Xi Jinping - who is supreme commander of the PLA and the People's Armed Police - to be his representative in the earthquake relief work.
When the premier told rescuers and local officials to act quickly, a commander of the air force told Li that it had sent 10 helicopters to drop food, water and shelter to the worst-hit areas.
Li kept his poise when the meeting was interrupted by aftershocks. During one, he concentrated on a map, then raised his head and asked with a smile: "What level was that aftershock?"
An official said it was probably of 4.0 magnitude.
Li also ordered the reopening of a blocked road to neighbouring Baoxing county. Later, he visited a temporary shelter in a secondary school elsewhere in Lushan county.