Schools were ordered shut from Saturday in the restive Indian state of Manipur after a rocket attack by insurgents killed a civilian and wounded six others.

Fighting broke out in the northeastern state more than a year ago between the predominantly Hindu Meitei majority and the mainly Christian Kuki community.

The conflict has simmered since then, splitting previously cohabitating communities along ethnic lines.

A local government notice said all schools in the state would be closed on Saturday, when classes are usually held, to protect the "safety of the students and teachers".

The day before, a rebel group had fired rockets in the state's Bishnupur district, an attack that local police attributed to "Kuki militants".

A police statement said a 78-year-old man was killed in the barrage and six people were wounded.

Officers responding to the attack "were fired upon by suspected Kuki militants but the police team retaliated robustly and repelled the attack", the statement said.

Local media reports said the elderly man was killed when a rocket hit the residence of the late Mairenbam Koireng Singh, a former chief minister of Manipur.

The Indian Express newspaper, citing an unnamed security source, said that the rockets appeared to be "improvised projectiles" made using "galvanised iron pipes attached to explosives".

Friday's attack came days after insurgents used drones to drop explosives in what police called a "significant escalation" of violence in the state.

A 31-year-old woman was killed and six people were wounded in that incident, which police described as an "unprecedented attack" by rebels.

Longstanding tensions between the Meitei and Kuki communities revolve around competition for land and public jobs, with rights activists accusing local leaders of exacerbating ethnic divisions for political gain.