India's government is warning of possible violent attacks by Maoist rebels in the coming days.
Maoist insurgents have called for a two-day protest, Monday and Tuesday, in an eastern part of India where they have considerable influence.
Additional Home Secretary D.R.S. Chaudary warned that the general strike may be accompanied by attacks against security forces, especially in five eastern states, Bihar, Chhattisgarh, Jhkarkhand, Orissa and West Bengal.
The warning follows an attack late Saturday in Chhattisgarh state, where authorities say at least 11 police officers were killed and another 11 wounded in a landmine explosion by suspected Maoist rebels.
The rebels operating there are part of a wider group of insurgents known as Naxalites.
They say they are fighting for the rights of the poor and landless. Their decades-long insurgency has left thousands dead, and Indian Prime Minister Manmohan Singh has called the Maoists India's gravest threat to internal security.