GUWAHATI, India, Nov 17, 2009 (AFP) - Suspected separatists blew up a fuel-laden train in India's restive northeast, causing a giant inferno that took 12 hours to control, police said Tuesday.

A police spokesperson said the train of 48 wagons travelling from the Numaligarh Refinery caught fire late Monday in the state of Assam about 270 kilometres (167 miles) from state capital Guwahati.

"It was initially thought the fire broke out after the train jumped rails. But now we believe it was due to a powerful explosion on the rail track as we managed to recover wires and other materials used in triggering blasts from the site," a senior Assam police official said, requesting not to be named.

The official said the outlawed United Liberation Front of Asom (ULFA) was the main suspect in the explosion which occurred near Changpool in Golaghat district.

The fire, which could be seen from five kilometres (three miles) away with flames estimated at 100 metres high, was brought under control mid-morning on Tuesday about 12 hours after the blast, police said.

Locals in the area said they heard a giant explosion and saw the train go up in flames.

A.K. Bhattacharrya, a marketing manager at the refinery, told AFP that "the damage is extensive" from the blast and 20 wagons carrying diesel and petrol were lost in the fire.

The area is a stronghold of both the ULFA and Adivasi tribal militants.

India's northeast is a large and remote area comprising seven states of which Assam is the biggest. More than 10,000 people have lost their lives to an insurgency in the past two decades.

More than two dozen rebel groups in the oil-rich northeast are fighting for secession.