The death toll from attacks by rebels on markets and a bus in India's north-eastern state of Assam has reached 23.
Police told the BBC that a group of heavily armed guerrillas waylaid the bus and opened fire indiscriminately.
Guerrillas launched another attack on a market in Assam's Dhekiajhuli region. Nineteen people died on the spot; four of the injured died later.
Police said the ambushes were carried out by the National Democratic Front of Bodoland (NDFB).
The NDFB want an independent homeland for the Bodo ethnic group to be carved out of Assam.
They have recently had a series of setbacks.
Police say the rebels appear to be on a "revenge killing spree" after last week threatening to kill "at least 20 Indians" to avenge the death of their commander, Mohan Basumatary, in a clash last month.
The group's chairman, Ranjan Daimary, was arrested in Bangladesh this year and handed over to stand trial in Assam.
He now faces charges of masterminding bomb explosions in October 2008, in which 87 people were killed.
But the rebels' military wing chief, B Sanjiabath, is still active with nearly 100 guerrillas.
Analysts say this hardline faction of the NDFB is trying to derail the peace process that Assam chief minister Tarun Gogoi wants to initiate, with the backing of the central government.
The Indian government has appointed an interlocutor - former intelligence bureau chief PC Haldar - to talk to the rebel groups in Assam.
The moderate faction of the NDFB is now in a ceasefire with the Indian security forces and wants to proceed with a peace process which the hard-liners want to derail, analysts say.