Suspected Maoist rebels triggered a powerful land mine Saturday that killed 13 policemen in eastern India, a top police official said.
At least two other policemen were injured in the explosion that blew up their minibus in Jharkhand state, police superintendent G.K. Rath said.
The officers had conducted a routine search for rebel hideouts in a remote, densely forested region and were returning from the operation when the blast occurred.
Police sealed off the district and launched a massive hunt for rebels active in the area.
The rebels have been fighting the government for more than four decades, demanding land and jobs for landless farmers and the poor.
Often referred to as Naxalites, for the village of Naxalbari in neighboring West Bengal state where the movement began in 1967, the fighters were inspired by Chinese revolutionary leader Mao Zedong.
Thousands of people, including police, militants and civilians, have died in the violence in recent years. The rebels are currently active in 20 of India's 28 states.