GAUHATI, India (AP) — Armed tribal rebels in northeast India attacked people from a rival tribe who were celebrating the popular holiday of Diwali, killing seven people, officials said Monday.

Up to nine rebels from the Garo tribe attacked people from the Rabha tribe Sunday night in the western Goalpara district of Assam state, District Magistrate Preetam Saikia said. At least 10 people were being treated for serious injuries.

Army troops and police officers were patrolling the area on the border with Meghalaya state, where a nighttime curfew was put into effect.

While none of the dozens of rebel groups active in the area has claimed responsibility, police said they suspect the Garo National Liberation Army. The group, which demands a separate Garo homeland, has emerged as one of the region's deadliest militant outfits, committing killings and kidnappings for ransom.

The Rabha dominate Assam, while the Garo are in the majority in neighboring Meghalaya.