Police in the north-eastern Indian state of Manipur say unidentified rebels have killed 14 Hindi-speaking migrant workers.
The victims came from the country's northern state of Bihar.
The migrants were attacked in three separate incidents that spread panic among local residents.
Attacks on Hindi-speaking migrants are rare in Manipur compared to neighbouring Assam where about 150 have been killed in last two years.
None of Manipur's many separatist rebel groups have said they carried out the attacks.
In the first incident, police said 20 rebels wearing olive green jackets and covering their faces with towels stormed a camp of workers at Mayai Lambi, not far from the state's capital Imphal, killing seven migrants.
"They were dragged out, lined up and shot dead," Manipur police chief Y Joykumar Singh said.
Another person, also a Hindi-speaker, was shot dead near Komlakhong village, under the same police jurisdiction, late on Monday.
It is not clear who was responsible for that killing either.
Hindi-speaking migrants have been targeted in neighbouring Assam
Residents remained indoors and the streets were deserted on Tuesday following the violence, local correspondents say.
Also on Tuesday, six more Hindi-speaking workers were kidnapped from Heiyen Hengun, under the same police jurisdiction, by armed rebels.
Three of them were found dead by the side of a road, all blindfolded and shot. The remaining three - initially thought to have been abducted - were also later found dead.
Manipur's separatist rebels have until now preferred to attack Indian security forces rather than civilian targets.
Separately, rebels belonging to the United National Liberation Front (UNLF), the strongest separatist group of Manipur, said they had killed six Indian soldiers in an attack on their outpost on the state's border with Burma this week.
The Indian army says only one soldier was killed and seven others were injured.
In neighbouring Assam state, rebels of the United Liberation Front of Assam (Ulfa) have regularly attacked Hindi-speakers.
The rebel group says Hindi-speaking migrants and settlers from India's heartland states like Uttar Pradesh and Bihar are threatening the indigenous people of the state.
They also accuse the incomers of being close to Indian security forces in Assam.