The first attack killed seven people including election officials and wounded five others when a landmine blast targeted their bus in the restive Chhattisgarh state on Saturday, senior police officer Gurjinder Pal Singh said.

The second attack killed five security men, an ambulance driver and a paramedic after rebels ambushed their vehicle.

The violence came as Indians cast ballots in the state of Goa and in the northeast during another round of the multi-phase elections that started last week. There was no voting in Chhattisgarh on Saturday.

India’s central region has been overwhelmed by three decades of insurgency.

The government forces have responded by stepping up security including imposing curfews and restrictions on the movement of people.

The rebels, however, say their fighting is aimed at gaining a greater share of the country’s resources.

On Monday, some 814 million eligible people began voting in the country, which has a population of 1.2 billion. The polls will close on May 12.

The vote is being held in stages, so security forces can readily move around the country to protect voters.

People in Chhattisgarh state are scheduled to cast their ballots next week.

India’s next government will face the tough job of reviving an economy plagued by high inflation and a wide fiscal deficit.