An armed separatist group is being blamed for killing at least 13 people and wounding more than a dozen during an attack on a busy weekly market in Kokrajhar town in India's northeastern Assam state, officials said.

One assailant was killed during the attack on Friday and security forces were in pursuit of three or four suspects believed to be hiding in a nearby forest, Assam police chief Mukesh Sahay told reporters.

Though no group has yet claimed responsibility, Sahay blamed the attack on the outlawed National Democratic Front of Bodoland, an armed group that has fought for decades for a separate homeland for the indigenous Bodo tribespeople in Assam.

"This attack is intended to destabilise peace in Assam," Himanta Biswa Sarma, the state's finance and health minister, told the Reuters news agency.

A second police official said that six attackers arrived in a motorised rickshaw and opened fire with automatic weapons and lobbed grenades into the crowded market in Balajan, just outside Kokrajhar town.

Speaking to Al Jazeera via Skype from the state's commerical capital Guwahati, local journalist Mrinal Talukdar said: "The wounded and the dead were innocent villagers. Among the injured were two children as well."

Three days ago, police arrested members of the Bodoland front with a cache of weapons in the same area as Friday's attack.

The Bodos are an indigenous tribe in Assam, making up 10 percent of the state's 33 million people.

Dialogue and discussion

Sanjoy Hazarika, director of the Centre for North East Studies and Policy Research in New Delhi, told Al Jazeera that the attack was a reminder that armed groups are still operating in the region.

“This is as good a time as any to remind the public that groups like this are still around," Hazarika said, adding that such groups "cannot be controlled just by the force of arms".

Hazarika said that "dialogue and discussion" would be required to bring such groups under control, "just as other groups have done".

Dozens of rebel groups have been fighting the Indian government and sometimes each other for many years in seven states in northeast India. They are demanding greater regional autonomy or independent homelands for the indigenous groups they represent.

The separatists target communities they consider outsiders, including Adivasis, whose ancestors migrated to Assam more than 100 years ago to work on tea plantations - as well as Muslims, accusing them and the federal government of exploiting the region's wealth while neglecting the locals.

More than 60 Muslim settlers and Adivasi tribespeople in Assam were killed in separate attacks in 2014.

In 2012 there were clashes between Bodos and mostly Bengali Muslim settlers that resulted in hundreds of deaths. Hundreds of thousands were displaced.

Deadly riots erupted again two years later.