BEIJING, Apr 20 (AP) -- A burst dam in northwestern China that forced the evacuation of 1,700 people is a warning that the country faces "time bombs" in thousands of its reservoirs, state media said Friday.

Deputy Minister of Water Resources Jiao Yong was quoted by the Xinhua News Agency as describing the structurally unsound reservoirs as "time bombs" that the government wants repaired within three years.

"The problematic reservoirs are like time bombs, seriously threatening the lives and property of people living downstream," the agency quoted Jiao as saying at a national meeting on efforts to repair the reservoirs.

Of China's 85,000 reservoirs, 30,000 had serious problems, the report said, including 200 large and 1,600 medium-sized reservoirs.

Jiao said in the report that the government would spend 5 billion yuan (US$647 million; €475 million) a year on repairs.

A dam on the Xiaohaizi reservoir in Gansu province cracked Thursday, flooding the surrounding area and destroying a highway bridge, Xinhua said.

The crack on the 10-meter (33-foot) -high dam measured 15 meters (49 feet), the report said, adding 1,700 people had to be evacuated from four villages.