The 300-year-old Qing dynasty tombs in northern China, which is protected as a UNESCO World Heritage site, is under threat from illegal mining, China News Service reported on Tuesday.

The Eastern Tombs, which are located about 125 kilometers east of Beijing, are the final resting place of more than 100 members of the Qing dynasty royal family, including 5 emperors.

However, illegal miners have flocked to the rich iron ore mining reserves in the area. Illegal mining has already destroyed part of the vegetation of the Shashan mountain, 200 meters away from one of the Eastern Tombs, AFP reported.

A villager from nearby Huida village said that illegal mining activities started two years ago. Mining has reportedly reached a depth of 50 to 80 meters. Explosions from the mines can be heard through the night and the iron ore is shipped out during the daytime.

China's cultural heritage law specifically prohibits explosions, mining and drilling in protected areas. A worker responsible for protecting the tombs said, though, that administrators responsible for the Eastern Tombs did not have the legal authority to prevent the illegal mining.

China had 33 sites listed in the UNESCO World Heritage list as of 2006.