Indian security forces killed at least 31 Maoist rebels on Sunday in one of the deadliest clashes since the government ramped up efforts to crush the long-running insurgency.

Two Indian commandos were also killed in the battle, and two other security force members were wounded, police said.

More than 10,000 people have been killed in the decades-long insurgency waged by the rebels, who say they are fighting for the rights of marginalised people in India’s resource-rich central regions.

“So far 31 dead bodies of the Maoists have been recovered,” senior police officer Sundarraj P. told AFP.

“Two security personnel are dead and two other security personnel are injured,” he added.

Reinforcements have been sent to the area, he said, warning that the toll could rise as the police carry out search operations.

“Additional forces have been rushed to the encounter site,” he said.

Police said they had seized assault rifles and grenade launchers from the bodies of the dead rebels.

The gunfight broke in the forested areas of Bijapur district in the state of Chhattisgarh, considered the heartland of the insurgency.

The rebels, also known as Naxalites after the district where their armed campaign began in 1967, were inspired by the Chinese revolutionary leader Mao Zedong.

“This is a big success in the direction of achieving a Naxal-free India,” said Amit Shah, India’s interior minister, who last year said the government expected to crush the rebellion by 2026.

Shah repeated his vow to “completely eradicate Naxalism”.

A crackdown by security forces killed around 287 rebels last year, an overwhelming majority in Chhattisgarh, according to government data.

More than 80 Maoists have been killed so far this year, according to a tally on Sunday by the Press Trust of India news agency.

The Maoists demand land, jobs and a share of the region’s immense natural resources for local residents.

They made inroads in a number of remote communities across India’s east and south, and the movement gained in strength and numbers until the early 2000s.

New Delhi then deployed tens of thousands of troops in a stretch of territory known as the “Red Corridor”.

The conflict has also seen scores of deadly attacks on government forces. A roadside bomb killed at least nine Indian troops last month.