The firm in Inner Mongolia is alleged to have knocked several holes through a section of the wall from the Qin dynasty (221-206 BC) while looking for gold, Wang Dafang, head of the northern region’s cultural relics office, told AFP.

Hohhot Kekao Mining ignored five orders to stop operations and continued to dig the holes, forcing the office to report the case to regional police, Wang said.

“For now, the case is under police investigation — around 100 metres of the wall have been damaged,” he said.

The official Xinhua news agency reported that China’s State Administration of Cultural Heritage had also sent a team to investigate the case.

The Qin Emperor, who unified China in 221 BC, began construction of the Great Wall as a defence against northern tribes, and it was subsequently re-built or extended by later emperors.

The wall currently stretches for more than 8,850 kilometres, but it is under threat from climate change and China’s massive infrastructure building, state media reported earlier this year.

In Inner Mongolia, miners, road construction workers and villagers collecting building materials have contributed to the ongoing destruction of the wall, the official Xinhua news agency reported.

Those guilty of damaging the World Heritage-listed site can be fined up to 500,000 yuan (73,000 dollars) or jailed for up to 10 years, Xinhua said.

Five miners were jailed for terms of one to three years last year in Inner Mongolia for damaging a section of the wall dating from the Ming Dynasty (1368-1644) while using heavy machinery.