(Updates toll to 15, adds quote)
By Sujoy Dhar
KOLKATA, India, Feb 15 About 100 Maoist rebels, many riding motorcycles, stormed a police camp in eastern India on Monday and killed at least 15 policemen as they fired indiscriminately and set fire to the site.
Police said the ambush was on a camp in the state of West Bengal, 200 km (125 miles) west of the state capital Kolkata, in the same area where a major anti-Maoist offensive was launched last year.
"No less than 15 security personnel were killed," senior police official Surajit Kar Purakayastha told Reuters in Kolkata.
In June last year, police pushed back the rebels to regain control of Lalgarh, a cluster of 150 villages in the same West Midnapore area.
West Bengal Director General of Police Bhupinder Singh said the rebels took away a huge cache of weapons in the latest assault.
A rebel group leader, who calls himself as Kishenji, telephoned a Kolkata-based news channel to claim responsibility for the attack.
"(It was) carried out to retaliate against the combined operation of West Bengal police and central paramilitary forces against the Maoists," he told the news channel.
The Maoist rebellion began four decades ago, championing the cause of poor peasants in the east, but has now spread to about 20 of India's 29 states, with the rebels targeting police and government property in hit-and-run attacks.
Prime Minister Manmohan Singh has warned the rebels have managed to retain support among a cross-section of society and remain the country's biggest internal security threat.
After a resounding general election win in May, the Congress party-led government has decided to take on an estimated 22,000 Maoist rebels who hold sway over swathes of countryside.
(Editing by Matthias Williams and Raju Gopalakrishnan)