IMPHAL: Three persons including a father-son duo were killed by militants in Manipur's Bishnupur district late night on Friday, police said.

The three were gunned down while they were sleeping and later slashed with swords at Kwakta in the district, police said on Saturday morning, adding that the assailants came from Churachandpur.

"The three used to stay in a relief camp but had returned to their residences at Kwakta on Friday after the situation had improved," police said.

Soon after the incident, an irate mob gathered at Kwakta and wanted to head towards Churachandpur but was stopped by security personnel, police said.

"Three persons including one policeman were injured following heavy exchange of fire between state forces and militants near Kwakta on Saturday morning. The policeman sustained splinter injuries on his face. All the three have been brought to Raj Medicity in Imphal for treatment. They are out of danger," police said.

Meanwhile, the district administration has shortened curfew relaxation hours in the twin Imphal districts because of the violence.

"Instead of curfew relaxation from 5am to 6pm in the twin Imphal districts, it has now been shortened to 5am to 10. 30am," an official said.

On August 4, Manipur police said a joint security force conducted an operation in the Koutruk hill range and destroyed as many as seven illegal bunkers.

Meanwhile, the 24-hour general strike called by the co-ordinating committee of 27 assembly constituencies in Manipur on Saturday paralysed normal life in Imphal Valley, with markets and business establishments remaining shut in almost all localities.