Insurgents exploded a series of bombs in different parts of Manipur late on Sunday night, hours before the start of polling for the second phase of Lok Sabha election in the state, official sources said.

However, no casualties were reported, the sources said.

The explosions were reported from Moirang in Bishenpur district and Uripok, Keisampat and Sagolband areas in Imphal West district and Sagang in Churachandpur district.

Insurgents also opened fire at a Central Reserve Police Force post at Kumbi area in Bishenpur district, the sources said.

Security measures have been tightened in the state, administrative sources said.