Unidentified gunmen have attacked two hideouts used by separatist fighters from north-eastern India in the Himalayan kingdom of Bhutan in the past 24 hours.
Four of the attackers and three rebels belonging to the outlawed United Liberation Front of Assam (Ulfa) were killed in the two encounters.
The Ulfa alleges that India is using mercenaries and surrendered militants to attack their hideouts.
But an Indian Home ministry spokesman said the encounters could be the result of infighting within the organisation.
Separatists from India's north-eastern state of Assam maintain a number of bases in southern Bhutan from where they attack targets in Assam.
Bhutan is under increasing Indian pressure to push the rebels out, and its foreign minister recently told the BBC he was giving them a "last chance" to leave.
The gunmen's identity was not yet clear but in a BBC interview, the Ulfa's publicity chief Ruby Bhuiyan alleged that "mercenaries hired by Indian intelligence" had teamed up with some former colleagues.
Bhutan has given Indian guerrillas a 'last chance' to leave
She said these joint teams had launched attacks against the Ulfa bases in southern Bhutan.
In the first incident, more than 15 gunmen attacked an Ulfa base at Kinzo, 22km from Bhutan's southern town of Samdrup Jongkhar, at midday on Sunday.
Ms Bhuiyan said two of their activists were killed but the gunmen fled when fighting broke out as other Ulfa guerrillas fought back.
She said another gang of 10 to 12 gunmen attacked Ulfa fighters sheltering at an abandoned house in Babang, 23km from Bhutan's Kawaipani town, just after sunrise on Monday.
Bhuiyan said Ulfa activists fought back and killed four of the gunmen but one of their own colleagues too died in the encounter.
The attacks were confirmed by district officials in Samdrup Jongkhar.
The Ulfa says the attackers were mercenaries and surrendered Ulfa militants, known as Sulfa in Assam.
Ruby Bhuiyan said they had been hired by Indian intelligence to carry out the attacks.
Earlier this year, unidentified gunmen had allegedly attacked the Ulfa's military wing chief Paresh Barua.
The group's Chairman, Arabinda Rajkhowa, has recently blamed Indian intelligence for kidnapping and killing one of his senior colleagues, Rustav Choudhury.
Last week, Bhutanese Foreign Minister Jigme Thinley told the BBC his government was giving the Indian guerrillas sheltering in Bhutan one last opportunity to leave peacefully.