At least seven Indian police officers were killed Sunday when their vehicle struck a landmine in the eastern region of the country.

Officials say they suspect the bombs were planted by Maoist rebels.

The attack was in Orissa state, nearly 550 kilometers south of the state capital Bhubaneshwar.

Indian officials say the long-running Maoist insurgency, which has spread to 20 of the country's 28 states, is India's most serious domestic security issue.  The rebels, also called Naxalites, are demanding land and jobs for the poor.

Some information for this report was provided by AP, AFP and Reuters.