Separatist rebels shot dead five people at a polling station in India's remote northeastern state of Manipur on Saturday during local elections, police said.

The heavily armed rebels killed three polling station officials and two others as they sprayed the station with bullets in Thangpi, a village south of the state capital Imphal, authorities said.

"The militants opened random fire at the voting centre, killing three polling centre officials, a paramilitary trooper and a civilian," police chief Priya Singh told AFP.

Two others were hurt in the attack, Singh said, adding that the militants fled the scene.

The attack came as heavy security was put in place across the impoverished state in a bid to thwart separatist militant attacks during elections for a new legislative assembly.