Five vehicles were buried over the weekend by mud flows as they attempted to leave quake-ravaged regions of Sichuan Province, and an estimated 200 people were known to have been on board, a transport official said on Monday.

The death toll was not confirmed as rescue work was still under way, said Director of Road Traffic Dai Dongchang with the Ministry of Transport in an interview.

The identities of the victims were yet to be confirmed, he said.

He cited incomplete statistics, saying at least 20,000 workers from Sichuan have been working round the clock to repair roads damaged by the quake.

As of Monday morning, two national highways leading to Wenchuan county, the quake's epicenter, had been reopened.

Only the highway between the counties of Wenchuan and Maoxian remains blocked, with a 7-km section still to be cleared, he said.

Once the section is opened, relief workers and materials will be able to enter Wenchuan directly from Gansu and other provinces to the north of Sichuan. Workers are also striving to open the road between Maoxian and Beichuan.

Part of the road has been reopened in Maoxian, but in Beichuan, workers have encountered a lake formed by the earthquake, he said.

"I must emphasize that the situation (of roads in the hardest-hit area) is still severe," he said.

The biggest threat comes from landslides triggered by continuous aftershocks and bad weather.

"It happens all too often that a road which has just been cleared is blocked again by a landslide," he said.

For example, the road between Lixian and Wenchuan has experienced three major aftershocks that measured more than 5 on the Richter scale since it was reopened, blocking the road again at several points.

"The workers are risking their lives racing against time, clearing the roads and keeping them open

"If you're not there, you can't understand the danger they face and their great courage," he said.

After a week's efforts, roads to at least 100 towns in the affected area have been reopened. Clearing and opening roads leading to the remaining 50 towns in the area is the next step, he said.

A trunk road network has taken shape, allowing the transportation of rescuers, medical workers, food and drugs into the affected areas, he said.

(Xinhua News Agency / China Daily May 20, 2008)