The official Xinhua News Agency put the death toll at 25 and said it was not known how many people were buried in the rubble. Another 361 people were injured by the earthquake that hit 31 miles southeast of Panzhihua city in the southwestern corner of Sichuan late Saturday afternoon, the administration said.
Nearly 400 houses were destroyed in Panzhihua while another 1,000 homes collapsed in the neighboring farming town of Liangshan, the statement said.
A woman who answered the phone at Sichuan provincial seismological bureau said the region was hit by about 300 aftershocks on Sunday morning, with the biggest measuring 3.3 on the Richter scale. She declined to give her name, saying she was not authorized to speak to the media.
The earthquake administration sent teams and seismic experts to the quake-hit area while the Yunnan provincial civil affairs bureau and the Yunnan Red Cross Society sent 3,400 tents and 2,000 quilts, Xinhua said.
Relief efforts were hampered by heavy rains and the region's rugged terrain, it said.
Dozens of evacuees were assembled on a field of a primary school in Panzhihua, footage from state broadcaster China Central Television showed Sunday in its midday bulletin.
Wrapped in quilts, the evacuees who included children and the elderly lay on plastic sheets and mats on the ground, the footage showed.
Also Saturday, an earthquake measuring 5.3 on the Richter scale struck the northwestern region of Xinjiang, Xinhua said in a separate report.
No casualties were reported from the quake that hit the sparsely inhabited Tianshan mountains although the tremor was felt in nearby counties and the city of Korla, the agency reported.
On May 12, a 7.9 magnitude earthquake in northern Sichuan killed nearly 70,000 people and left 5 million homeless. The region has been hit by scores of aftershocks, keeping people there on edge.