India has announced that it arrested a top rebel leader on Monday who is allegedly responsible for a deadly attack on an army convoy four weeks ago.
Last month's attack took place in the northeastern state of Manipur, near the border with Myanmar.
Guerrillas killed 20 soldiers and wounded 11 others, firing rocket-propelled grenades and detonating improvised explosive devices. The Indian army conducted cross-border operations against rebel camps after the attack.
India's National Investigation Agency (NIA) said the leader of the separatist National Socialist Council of Nagaland, Khumlo Abi Anal, is the first arrest in the case.
"Investigation has revealed that the accused was extensively involved in the conspiracy to attack the army personnel," the NIA said in a statement.
Meanwhile, a Times of India report has suggested that Anal "got himself arrested in a different case to evade his role in the killings" but admitted his role in the ambush after "sustained questioning."
Many armed groups operate in India's northeastern states, some demanding separate states and others fighting for a greater autonomy. They accuse the Indian government of negligence and exploitation of natural resources.
Most rebel groups in Manipur have not joined talks with the Indian authorities that aim to bring about a ceasefire deal.