BEIJING (REUTERS) - China has consistently demanded its companies operating abroad respect local laws, China's Foreign Ministry said on Monday (May 9) after hundreds of villagers in Myanmar protested against the resumption of operations at a Chinese-backed copper mine.

The protests have gathered momentum since last Wednesday when some people broke through police barriers protecting the mine, operated by Myanmar Wanbao, a unit of a Chinese weapons maker, in one of the first tests for the new government's ability to deal with public anger.

Myanmar Wanbao runs the Letpadaung mine in a joint venture with a conglomerate controlled by the Myanmar military, Myanmar Economic Holdings Ltd. Villagers say their land has been unlawfully confiscated to expand the mine.

Chinese Foreign Ministry spokesman Lu Kang, asked about the protests, said China and Myanmar are traditional friends whose cooperation accords with the interests of both countries.

"The Chinese government has consistently demanded that Chinese companies investing abroad respect the laws and rules of the host nation, and fulfil their responsibility and obligation to society, including paying attention to protecting the environment," Lu told a daily news briefing in Beijing.

"China is willing to work hard with Myanmar to properly implement these mutually beneficial cooperation projects, to promote local socio-economic development, to better benefit both countries and their peoples," he added.

Chinese Foreign Minister Wang Yi visited Myanmar last month, where he said China was confident it could resolve business disagreements with Myanmar through friendly talks, amid pressure from China to resume a stalled US$3.6-billion (S$4.9-billion) dam project.

Lu said China was confident it could continue to have win-win cooperation with the country formerly called Burma.

After big protests in 2012 and 2013 against the mine, when riot police raided a protest camp injuring more than 100 people, then opposition leader Aung San Suu Kyi led an inquiry that recommended compensating the residents and minimising environmental damage.

Suu Kyi led her party to a sweeping election victory last year and now oversees the government.

Work at the mine, about 100km west of the city of Mandalay, was suspended after the 2012/13 protests. The company has recently tried to show it can reduce the impact of mining and improve livelihoods.

China has made a big push to assert its business and political interests since Suu Kyi's party took over in April.

In 2012, police threw white phosphorus grenades at protesters, inflicting serious burns on scores. In 2014, a protester was shot dead.