New Delhi - At least 17 people were killed and 30 injured in a bomb blast suspected to be carried out by separatist militants in India's north-eastern state of Manipur on Tuesday, news reports said.

The bomb was planted on a motorcycle and exploded near the police commando barracks in Imphal, the state's main city.

Imphal police sources told the PTI news agency that 13 people were killed on the scene, and four succumbed to injuries at the hospital.

Most of the victims were civilians, but some could be policemen.

"We are not yet sure if any of the police commandos are among those killed or injured," Imphal police superintendent Radhe Shyam told the IANS news agency.

The injured were rushed to various hospitals in the city where doctors said the death-toll could rise as several injured were in serious condition.

This was the biggest bombing in the Manipur capital, a heavily guarded city which has seen several attacks and bombings by separatist militants.

No militant outfit has claimed responsibility for the attack. The bombing comes two days after a grenade attack outside the state chief minister's house.

A militant outfit the People's Revolutionary Party of Kangleipak (PREPAK) had claimed responsibility for Sunday's attack.

The PREPAK has been fighting security forces over the last three decades for an independent homeland for the majority Metei community.

There are more than 19 militant groups active in Manipur, bordering Myanmar, with demands ranging from secession to greater autonomy.

India's north-east is a volatile region where nearly 40 separatist, tribal or leftist groups are active in five states. More than 15,000 people have lost their lives to insurgency in the region in the past decade. (dpa)