At least 17 police commandos killed after their patrol came under attack in a remote area of Sukma district.

Maoist rebels have killed 17 Indian security forces in an ambush in central state of Chhattisgarh, a police spokesman said, in the deadliest attacks in recent years.

More than 300 armed rebels took part in the attack on a police commando patrol in the jungles of Sukma district, police superintendent Shalab Sinha told AFP news agency.

Large numbers of reinforcements were sent to the district on Sunday.

“We have recovered 17 bodies and another 15 police are being treated for injuries,” he said.

“We believe the ambush was carried out by between 300 and 350 attackers.”

Other officials said four Maoists were killed in the battle on Saturday.

Prime Minister Narendra Modi condemned the attack. “My tributes to the security personnel martyred in the attack. Their valour will never be forgotten. Condolences to the bereaved families,” he posted on Twitter.

The toll was the worst for Indian security forces battling the left-wing rebels since April 2017 when 25 police commandos were killed in an attack in the same district.

Sixteen commandos were also killed in a bomb attack in the western state of Maharashtra before India’s election last year that was blamed on the Maoists.

The far-left rebels, also locally known as Naxals, have been fighting in eastern, central and southern forest areas since the 1960s, demanding more rights for the poor and for tribal groups.

Indigenous people who inhabit the mineral-rich regions, have been caught in the middle of a conflict that has pitted the Maoists against government forces. Thousands of people, mostly tribal people have been killed.

Security forces have been accused of committing rights abuses and extrajudicial killings of innocent indigenous people. Human rights activists and journalists have been dubbed “urban Naxals” and targeted for reporting the abuse and unlawful killings.