Civilian rescuers drag a seriously wounded man from a blast site in Gauhati, India, yesterday.

A series of bombs planted in cars and rickshaws ripped through markets crowded with lunchtime shoppers in India's volatile northeast yesterday, killing at least 61 people and wounding more than 300.

The 13 co-ordinated blasts surprised authorities, who struggled to pinpoint who was behind the attacks — among the worst ever to hit the region, which is plagued by separatism, ethnic violence and Islamic militants.

The largest explosion took place near the office of the Assam state's top government official, leaving bodies, cars and motorcycles strewn across the road.

Bystanders dragged the wounded and dead to cars that took them to hospitals. Police officers covered the burned remains of the dead with white sheets, leaving them in the street.

Sixty-one people were killed in the blasts, including at least 31 killed in five explosions in the state capital, Gauhati, said Subhash Das, a senior official in the state's Home Ministry. At least 19 people were killed in blasts in the Kokrajhar district and 11 others in the town of Barpeta, he said

At least 300 people were injured in the explosions just before noon, Das said.

Officials were quick to blame the region's largest separatist group, the United Liberation Front of Asom.

“The needle of suspicion is on ULFA,” said Assam official Himanta Biswa Sharma.

However, ULFA has never carried out an attack of this size, which closely resembles the serial attacks that have rocked three other Indian cities this year, killing more than 120 people — attacks claimed by a previously unknown Indian Islamist militant group.

“Going by the nature, planning and magnitude of the blasts we need to find out if ULFA has been assisted by other terror groups ... at home or abroad,” said Das.

ULFA spokesman Anjan Borehaur denied his organisation had any role in the attacks in an e-mail sent to journalists.