Maoists rebels burned down a tractor and some machinery at the construction site of a bridge in India's eastern Jharkhand state on Thursday.

The incident took place at a village around 90 miles from the state capital of Ranchi.

Maoists have been demanding taxes from construction contractors. The Maoists often cause considerable damage to construction work in progress when the contractors are unable to pay.

[Rajesh Sahu, Contractor]:
"The machines have been damaged whereas we have been threatened that we'll be killed. We are working here by risking our lives just to maintain our dignity.”

Police are searching for clues as to who’s responsible, but haven’t come up with any leads yet.

Indian Prime Minister Manmohan Singh has described the Maoist insurgency as the gravest threat to India's internal security.