YANGON, Myanmar (AP) -- An independent investigation has found that white phosphorus caused the severe burns monks and other demonstrators suffered during a November crackdown by police on a protest against a mining project in northwestern Myanmar, a lawyer said.
The crackdown left more than 100 people, mostly Buddhist monks, with burns that authorities said were caused by tear gas and smoke grenades.
But an analysis at a Bangkok laboratory found traces of white phosphorous in canisters that were left by police and later recovered by a group of lawyers at the Letpaduang copper mine, where officers broke up an 11-day occupation by protesters, lawyer Aung Thein said Thursday.
White phosphorus is an incendiary agent generally used in war to create smoke screens. Guidance on its use against people is conflicting.
Aung Thein was not directly involved in the investigation, which was conducted privately by the lawyers, but he signed the report on the findings. The report has been forwarded to the government-appointed panel headed by opposition leader Aung San Suu Kyi that investigated the incident.
"Such devices that could cause serious injury should not be used to disperse peaceful protesters," Aung Thein said.
Myanmar's government spokesman declined to comment on the findings.
"Only the report of the Investigation Commission led by Daw Aung San Suu Kyi will be final," presidential spokesman and deputy information minister Ye Htut said in an email Friday. Daw is a term of respect in Myanmar.
Ye Htut said he was not aware of which experts were on the body or where the study was conducted.
The mining project in Monywa is a joint venture between a military-controlled holding company and China's Wanbao Mining Copper Ltd., a subsidiary of NORINCO, a Chinese weapons manufacturer. Protesters wanted the project halted, saying it caused environmental, social and health problems.
Myanmar's government had said that police used water cannons, tear gas and smoke bombs to disperse the protesters on Nov. 29, though many wondered what caused the serious burn injuries.
The incident marked the biggest use of force against protesters in Myanmar since the reformist government of President Thein Sein took office in March 2011.
The heavy-handed action indicated that the government was still unsure where to draw the line on public protests, even though Thein Sein's administration has been hailed for releasing hundreds of political prisoners and implementing laws allowing public demonstrations and labor strikes.
The Suu Kyi-headed commission is to submit its findings to Thein Sein and advise whether the mining project should continue.