Anti-drug activists say the military and local police are preventing them from destroying fields of opium poppies in northern Myanmar, a major cultivation area for the drug that can be made into heroin.

The Pat Jasan group has about 1,000 members engaged in the eradication campaign and is affiliated with Christian churches of the Kachin ethnic minority. The effort it started in late January is opposed by farmers and militias that profit from drug trafficking.

Three Pat Jasan activists have been injured by land mines and one 19-year-old member has been shot dead. The group claims to have destroyed many acres (hectares) of poppies.

Officials with the state anti-drug police failed to respond to requests for comment Friday.

Myanmar is the world's second-biggest producer of opium after Afghanistan.