Heavy rain is hampering efforts by Chinese emergency workers to drain a so-called "quake lake" that was formed by this month's deadly earthquake in southwestern Sichuan province.

More than 150,000 people have been evacuated from the area below Tangjiashan lake, which was formed after landslides triggered by the May 12 quake caused natural dams to form in rivers. Authorities fear the lake could overflow and trigger flash floods in the area.

The heavy rains have grounded helicopters from airlifting equipment needed to help in the drainage of the lake.

Officials have allocated millions of dollars to deal with that lake and more than two dozen others like it.

Chinese officials say the death toll from the earthquake has surpassed 68,000, with nearly 20,000 more people missing.

Japan's Foreign Ministry announced Wednesday that Chinese officials have asked its military to fly relief supplies to China. Japan says it is considering the offer. If Japan agrees, it would be the first time its military has been deployed to China since the end of World War II.

Some information for this report was provided by AFP, AP and Reuters.