THIMPHU, Bhutan Jan 1 Four forest rangers were killed by a landmine planted by communist guerrillas at a Bhutanese village, police said on Thursday.
"Six Bhutanese forest rangers were returning to their camp after shopping when the tractor they were travelling in hit a landmine planted on the road," a police statement said.
The attackers fired at the rangers after the explosion on Dec. 30 at Singye village near a wildlife sanctuary, 250 km (155 miles) south of the capital Thimphu.
One forester escaped with two bullet injuries and informed the police. Another who had hidden in the jungle was rescued by a search team late in the night.
Police said the attackers, from the banned Communist Party of Bhutan based in UN-run Bhutanese refugee camps in Nepal, dragged the bodies of the dead rangers into the burning tractor tyres and took two rifles with ammunition, and a walkie-talkie.
Bhutanese police and the army beefed up security along the 699-km (435 mile) unfenced border with India after the incident.
The Party has been demanding the repatriation of around 100,000 Bhutanese refugees who have been living in the camps for nearly two decades.
Tens of thousands of ethnic Nepalis in southern Bhutan fled or were expelled to Nepal in the 1990s after demanding greater democracy and respect for Nepali rights in the tiny Himalayan country. Bhutan says most of them are illegal immigrants who left of their own accord.
Bhutan's first democratically elected government, which came to power last April after a century of royal rule, says the refugee crisis will be solved very soon.
The Communist Party of Bhutan says it does not trust the government and is ready to wage a 'People's War'. They have also attacked refugees who opted for third country resettlement in Western countries including the United States.
Three bombs exploded at an office of the International Organisation of Migration (IOM) in Nepal last July, which has been processing the resettlement of around 60,000 refugees to the United States and Europe.
Bhutan's army destroyed three of the Party's camps in forests and caught 12 activists with weapons and explosives in 2008. (Editing by Matthias Williams and Philippa Fletcher)