Imphal: One person was killed when unidentified militants exploded a bomb in front of the house of the Manipur Assembly Speaker I Hemachandra Singh at Singemei in Imphal West district on Sunday, police said.

In their continued attack on Congress leaders and workers in the state going to assembly poll on January 28, militants hurled the bomb before the house of the speaker and one passer-by was killed. The victim's identity was yet to be established.

The speaker is safe, police said.

Two grenades were lobbed targeting two Congress workers Ningombam Gojen (45) and N Rojen (50)in Thoubal district during the day, but they escaped unharmed, police said.

Seven insurgent outfits had announced soon after the poll notification that they would attack Congress candidates, leaders and workers as the party opposed their "cause".

Since then almost every day Congressmen were under attack by the militants. They also attacked a Trinamool Congress candidate a few days ago, police said.