Two Peruvian soldiers and four rebels have been killed in the latest clash in the country's main drug growing region, the government says, BBC reported.
The Defence Ministry described the rebels as "narco-terrorists," belonging to remnants of the Maoist Shining Path movement who joined drug traffickers.
It was the first time this year that the military says it killed rebels.
Thirty-eight soldiers have been killed in ambushes in the year since the military was sent into the area.
The clash happened on a drug-smuggling route out of Peru's top coca-growing valley, the Associated Press reported.
Soldiers were pursuing rebels near the mountain community of San Antonio de Carrizal, Defence Minister Rafael Rey said.
Last year, the Shining Path sprang back from relative obscurity to launch a series of deadly attacks, killing some 25 soldiers and police officers in ambushes and gun battles.
But the group is believed to be a fraction of its former size and is split between two cocaine-producing zones of Peru, some 500km (310 miles) apart.
It is made up of a few hundred guerrillas who did not lay down their arms when the group's leader, Abimael Guzman, declared the armed revolution at an end after his capture in 1992.
Its fighters are considered expert in guerrilla warfare from years of resistance in some of Peru's remotest and wildest country and are well-armed from the profits of the cocaine trade.