LUSHAN, Sichuan - New threats and hazards began to loom on Tuesday as rescue and relief efforts entered a fourth day since the 7.0-magnitude struck in Lushan county in Southwest China's Sichuan province.

Rain began falling in the morning in the region, hampering relief work and posing threats such as rain-triggered landslides and possible outbreaks of disease.

In the village of Yuxi in Baosheng township, hundreds of residents have moved from tents they built to water-resistant ones.

Armed police have set up 20 tents for villagers and helped them move their daily necessities inside.

According to the National Meteorological Center, moderate rain will linger in the quake-hit region over the next few days, adding to difficulties in carrying out relief work.

"Such weather is hampering our rescue and relief work, and it's risky to operate large machines under such conditions," said Zhang Yefu, an engineer who is leading a team to build makeshift shelters in Lushan county seat.

Sanitation conditions in the region are far from satisfactory as there is not enough clean water and locals are in need of toilets.

"People in the town are drinking water from wells or mountain springs, but we have no idea if it is clean enough or adequate," said 43-year-old Yang Yumei, from the township of Lingguan in Baoxing county. Baoxing is one of the counties that was worst hit by the quake.

Zhang Zuyun, deputy head of Sichuan Provincial Health Department, said providing safe and clean drinking water to locals is a problem, noting that some people are suffering from diarrhea.

Zhang said the local health authority is trying to send a water quality testing machine to the town.

In a settlement in Lingguan Middle School, tents have been set up to accommodate nearly 1,000 people, who have to share a few toilets in the school building.

As running water and electricity have been cut off, the toilets are getting dirty.

A disaster relief team from the Chengdu Military Region Air Force began carrying out epidemic prevention work by spraying insecticide and disinfectant in worst-hit regions.

He Qiang, a health director with the air force, said mosquitos must be killed and excrement and garbage properly handled.

"Epidemic prevention is a focus of post-quake relief and aid work, although no epidemic outbreaks have been reported so far," said Zheng Xuexiang, logistics director with the air force.

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