Police suspect that the landmine was laid and triggered by leftist Naxals rebels active in the area.
The blast took place Tuesday evening along a road near Budha Pahar in Garhwa district, about 250 km northwest of Ranchi, the capital city of Jharkhand.
"Six policemen belonging to Jharkhand Jaguar Force were killed and four others wounded in a blast here that flung off the vehicle they were travelling," a police official posted in Garhwa said.
"The wounded were immediately airlifted to hospital for advanced treatment."
A senior police official Vipul Shukla told media the police got information that some Naxals were present in the Chinjo area of Garhwa district, after which they sent a contingent to carry out searches.
Reports said following the attack Naxals looted weapons of the policemen.
Naxal rebels are active in more than a third of India's 600-odd districts across central and eastern India.
New Delhi has deployed several companies of its paramilitary forces to take on Naxals in their strongholds.
Reports say the insurgency has claimed more than 6,000 lives and rendered thousands of poor inhabitants homeless.
More about: #India
