Eight people have been killed in clashes between the police and protesters over tribal rights laws in the north-eastern Indian state of Manipur, officials say.

More than 30 people have been injured in violence, which began on Monday.

Angry mobs have set the houses of six local lawmakers on fire. Curfew has been imposed in some districts.

The unrest has been triggered by three controversial bills aimed at giving more rights to indigenous groups.

The federal government has called the situation "very tense" and offered to send soldiers to defuse the situation.

The violence erupted late on Monday when three people were allegedly killed in police firing after a mob attempted to attack and torch a police station in the Churachandpur district, reports say.

Five others died after a strike called by an indigenous students group to protest the legislation turned violent on Tuesday.

The homes of a state minister, a member of parliament and five state legislators were also set on fire.

Tensions have been rising in recent weeks ahead of the vote on the three bills aimed at giving more rights to indigenous groups who accuse "outsiders" of taking land and jobs.

The groups have concerns over a clause setting 1951 as the base year for classing residents as indigenous, with those settling in the state before then given land rights, activist Babloo Loitongbam told the AFP news agency.

He said that those who fled rebel fighting in neighbouring Mizoram state in the 1960s for Manipur along with ethnic Chins who fled Myanmar in the same decade, fear they will classed as "outsiders".