More than 1.5 million people have been affected by the quake, with at least 186 people confirmed dead, China's Xinhua news agency reported. More than 1,700 aftershocks have been reported, the greatest measuring 5.4 on the Richter scale.
Roads blocked by boulders shaken loose from mountains were preventing military and civilian rescue teams from reaching households in Lushan County and other nearby counties, the rescue headquarters of the Chengdu Military Area Command said earlier.
Of the 18,000 soldiers and officers sent to the affected areas from the country's military, 10,000 have reached their designated areas, a statement from the command said.
Twenty-three military helicopters will be dispatched to transport relief materials, Xinhua reported.
The provincial emergency response command center said 186 people were killed by the quake, while 11,393 others were injured and 21 are missing as of Sunday.
The quake struck just after 8 a.m. Saturday in Lushan County and had a depth of about 7.5 miles, Xinhua said.
On Sunday, the China Earthquake Administration held its third meeting since the quake happened and determined that it would conduct damage evaluation and quake forecasting, and publish relevant information concerning the disaster in a timely manner.
The CEA has sent 15 seismologists and other experts from the Ministry of Housing and Urban-Rural Development to assess the damage caused by the quake, Xinhua reported.