LUSHAN, Sichuan - Continual aftershocks and insufficient relief supplies are hampering the rescue efforts in southwest China's Sichuan, 36 hours after a powerful tremor hit the province.

The latest statistics showed that at least 186 people have been confirmed dead and more than 1.5 million affected as of Sunday night, according to the provincial relief authorities.

Earthquake Strikes Ya'an, Sichuan

Rescuers are racing against the "critical first 72 hours after the disaster" to comb the quake rubble and reach every household in the epicenter of Lushan and its neighboring counties affected by a 7.0-magnitude earthquake that jolted the city of Ya'an early Saturday.

Over 1,700 aftershocks have been monitored in Lushan as of 10 p.m., with the strongest measuring 5.4-magnitude, making the already ramshackle houses even more dangerous and the rescue efforts more life-threatening.

A rescue excavator plunged off a 300-meter deep cliff in the morning in Ya'an's quake-hit Baoxing county. The number of casualties have remained unknown as of Sunday night.

"Lifeline" resumes

As of 5 pm, traffic has resumed on the road linking Baoxing to its neighboring counties of Lushan and Xiaojin and the city of Dujiangyan, resuming transportation of the stranded relief supplies to the county after its 33 hours' post-quake isolation, according to the Sichuan Provincial Department of Transportation.

The road is dubbed as the relief "lifeline" by rescuers.

Several rescue teams managed to reach Baoxing, which has a population of 60,000 and had remained hard to to access after the quake. At least 26 locals have been confirmed dead with another 2,500 being injured as of Sunday morning, according to county head Ma Jun.

"The top priority is to save lives," said Ma. "Meanwhile, we'll resettle the residents and reopen roads."

Altogether 40,000 homeless Baoxing residents are waiting to be relocated as most houses in Lingguan Township and Daxi Village in the county have suffered damage.

Airborne remote sensing images showed that more than 60 percent of buildings in the county seat had suffered damage.

Power supplies have been restored in only a few villages in Baoxing, the most part of which is still shrouded in darkness.