* Death toll almost 10,000 in Sichuan, many more feared dead

* Government urges aid drive, warns on social stability

* Chinese shares open down more than 3 percent after quake

* Wen orders roads to worst-hit Wenchuan county to be opened (Adds details, quotes from Dujiangyan throughout)

By Ben Blanchard

DUJIANGYAN, China, May 13 (Reuters) - Nearly 10,000 people were killed by the earthquake that hammered southwest China, officials said on Tuesday, as rescuers struggled to reach the worst-hit areas where many more may have died.

The toll from China's worst earthquake in three decades appeared sure to rise as troops struggled on foot to reach the epicentre, Sichuan province's Wenchuan, a hilly county about 100 km (62 miles) from the provincial capital Chengdu.

Chinese Premier Wen Jiabao, who rushed to Sichuan, ordered roads to Wenchuan, completely cut off by Monday's 7.9 magnitude quake, to be opened by midday, the official Xinhua news agency reported.

But rain and thick clouds meant that military helicopters dispatched to the area could not yet land, and if the weather remained overcast soldiers would try to parachute in.

In the Sichuan city of Dujiangyan -- about midway between Chengdu and the epicentre -- there were scenes of devastation, with buildings reduced to rubble and bodies in the streets, some only partially covered.

Troops and ambulances thronged the streets, and military trucks able to do heavy lifting had arrived. But many residents simply stood beside their wrecked homes, cradling possessions in their arms, and many huddled in relief tents under heavy rain.

"At least 60 or 70 old people lived there, as well as children," said a hospital worker surnamed Huo, gesturing to a building in ruins. Mattresses and household objects could be seen poking through the rubble.

"How could they survive that?" she asked.

Rescuers had worked frantically through the night, pulling bodies from homes, schools and 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. Premier Wen bowed three times in grief before some of the first 50 bodies pulled out, Xinhua news agency reported.

"Not one minute can be wasted," said Wen, a trained geologist. "One minute, one second could mean a child's life."

At a second school in Dujiangyan, fewer than 100 of 420 students survived, Xinhua reported.

The initial tremor, which the U.S. Geological Survey upgraded to magnitude 7.9 from 7.8, was followed by a series of aftershocks, which shook the area through the night.

"Some are still very strong," said a Dujiangyan resident reached by telephone. "We have put up tents outside to sleep in."

"TIME IS LIFE"

China's benchmark stock index <.SSEC> opened down more than 3 percent after the quake, which forced the suspension of trading in the shares of 66 companies, but quickly recovered some ground, trading down 0.4 percent at 0206 GMT.

China's Communist Party leadership announced that coping with the devastating quake and ensuring that it did not threaten social stability were now the government's priorities.

"Time is life," said an official announcement from the Communist Party Standing Committee. "Make fighting the earthquake and rescue work the current top task."

Officials must speed food, water, medicine and other necessities to quake-stricken areas, the meeting ordered.

"Strengthen positive guidance of opinion," the meeting urged, warning against the spread of rumours.

The Sichuan quake was the worst to hit China since the 1976 Tangshan tremor in northeastern China where up to 300,000 died. Then, unlike now, the Communist Party kept a tight lid on information about the extent of the disaster.

Neighbouring areas were also affected, with 150 reported dead in Longnan city of the northwestern province of Gansu and school collapses in the municipality of Chongqing.

In Gansu, the quake caused a train to derail, spilling petrol tanks and sparking a fire, Xinhua reported.

In Sichuan's Shifang, where the quake sparked a major chemical leak, about 600 people died and as many as 2,300 remained buried, Xinhua said. Two chemical plants collapsed, causing more than 80 tonnes of liquid ammonia to leak out.

In Chengdu, many residents slept outside or in cars as aftershocks were felt through the night in a city where at least 45 people died and 600 were injured.

Local radio broadcast appeals for people to leave their cars at home to make way for emergency vehicles.

"At this time of disaster, we are one family," radio said. "We are confident that under the leadership of the Party, families can be reunited and we can leave this nightmare."

Wenchuan officials described crumpled houses, landslides and scenes of desperation. Xinhua said some half a million houses in the area had collapsed.

A paramilitary officer marching with a hundred troops towards Wenchuan described a devastated landscape.

"I have seen many collapsed civilian houses and the rocks dropped from mountains on the roadside are everywhere," Xinhua quoted People's Armed Police officer Liu Zaiyuan as saying. (Writing by Chris Buckley and Lindsay Beck; Editing by Ken Wills and John Chalmers)

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