RAIPUR, India: Maoist militants killed 15 police officers in the jungles of India's central state of Chhattisgarh in two separate bomb blasts, police said on Friday, as the insurgents continued a fresh round of violent attacks on security forces.

A bomb attack on two security vehicle killed 10 police and injured three early on Friday morning, a senior police officer said, hours after insurgents shot dead five state policemen in a raid on an armed forces camp.

Both the attacks were carried out in forested areas of the mineral rich region where the Maoists are mainly active, and where widespread violence has worried investors and disrupted mining and rail transport.

“It was a massive blast,” Ram Niwas, additional director general of police (Maoist operation), told Reuters.

The anti-landmine vehicle was tossed up in the air by the blast before it landed in pieces, Niwas said. The attack took place 400 kilometres from the state capital, Raipur.

A recent crackdown on rebel-controlled areas had raised hopes that the government was winning the battle against what the prime minister has described as India's biggest internal security threat.

But the latest string of attacks, including a blast last month that killed seven policemen, has led to fears that security forces are ill-prepared to deal with the threat.

The Maoists' campaign against the government began as a peasant revolt in the late 1960s. The militants say they are fighting for the rights of the poor and the disenfranchised.