The death toll in yesterday's earthquake in China has now surpassed 12,000, according to the latest official reports.
State media reports indicated that the number of dead from the 7.9 magnitude quake was likely to soar.
Some 18,645 people are buried under rubble in Mianyang district alone, state media said today.
Heavy rainfall and wrecked roads hampered efforts to reach areas hardest-hit by China's worst earthquake in three decades today as the death toll rose to nearly 12,000.
Xinhua news agency said 10,000 people were buried in the Mianzhu area of south-western Sichuan province alone. Troops had also arrived for the first time at Wenchuan county, the epicentre of the quake.
"The death toll from this disaster has already reached 11,921," Wang Zhenyao, disaster relief chief under the Ministry of Civil Affairs, told reporters.
"The first priority is to save people. . . As long as there is the slightest hope, we will try to save them," Mr Wang said, adding that the biggest threat to life was now mudslides.
It was not immediately clear whether Mr Wang's toll was confined to Sichuan province. Hundreds more have perished in neighbouring provinces.
A strong aftershock rocked Chengdu, capital of Sichuan, this afternoon, one of more than 1,950 over the past day and keeping nervous residents on edge.
Premier Wen Jiabao, who rushed to Sichuan, ordered troops to clear roads to Wenchuan, a hilly area about 100 km (62 miles) from the provincial capital Chengdu.
Damage from Monday's quake left the area cut off.
But rain and clouds meant that military helicopters dispatched to the area could not yet land, and if the weather remained overcast soldiers mobilised to help with rescue work would try to parachute in.
State television showed highways buckled and caved in from the quake and massive rockslides lining the roads.
In the Sichuan city of Dujiangyan -about midway between Chengdu and the epicentre - buildings reduced to rubble and bodies in the streets, some only partially covered.
Rescuers had worked frantically through the night, pulling bodies from homes, schools, factories and hospitals demolished by the quake, which rolled from Sichuan across much of China.
In the same city, about 900 teenagers were buried under a collapsed three-storey school building.
At a second school in Dujiangyan, fewer than 100 of 420 students survived, Xinhua reported.