Five people were killed in election related violence in India's isolated, northeastern state of Manipur, police said on Saturday.

Among those who died were a woman, a security guard and three election duty staff, when suspected tribal rebels attacked a polling booth in the state's Chandel district.

The militants are suspected to be from the National Socialist Council of Nagaland faction, a police officer said.

No group, however, has so far claimed responsibility for the attack.

Strife-ridden Manipur, bordering Myanmar, is the first of five Indian states to go to polls in early 2012 to elect a state legislature.

The Congress party, which leads the federal coaltion government, is expected to retain office.

CorCom, an alliance of seven separatist Manipuri groups who view India as a colonial power, blamed the Congress government for degeneration of the Manipuri society ... to the present state of social, moral, economic and political bankruptcy.

We are fighting against the Indian occupation of Manipur. So as a part of fighting Indian occupation we ban the Congress and their agents in Manipur, the alliance said in an e-mail received by Reuters late on Friday.

The group claimed responsibility for a grenade attack on a Congress candidate's home last week.

(Additional reporting and writing by Arup Roychoudhury in NEW DELHI; Editing by Ed Lane)