The latest attack struck at Hindi-speaking settlers in Haluakhuwa, 530km east of the state capital Guwahati, police said on Sunday.
Assam's police chief Khagen Sharma told journalists one resident was also seriously injured when assailants torched five homes.
In an earlier attack, police confirmed 11 Hindi-speaking labourers were gunned down by suspected rebels who attacked two brick kilns in the eastern Tinsukia district.
The violence began on 15 November when Assamese separatists prevented candidates from the Hindi-speaking state of Bihar from taking recruitment tests in the state for railway jobs.
Youths in Bihar retaliated by attacking trains to Assam, injuring around 50 people.
The rebel United Liberation Front of Assam (ULFA) then warned all settlers from India's densely populated Ganges Plain to leave.
Sharma said the attacks on Saturday were all believed to have been carried out by the ULFA, which is fighting for a separate homeland in Assam.
More than 10,000 people have been killed in insurgency in the past two decades.
"The situation is indeed very serious and we shall not allow it to further escalate"
federal minister for north eastern India's development
Around 40% of India's billion-plus people are native Hindi speakers, including most of the country's top political leaders.
Assamese rebels accuse Hindi-speaking settlers of altering the demographic balance and taking away jobs.
Dr Thakur, the federal minister for northeastern India's development, visited Assam on Saturday and said the ethnic violence had become "a national problem".
"The situation is indeed very serious and we shall not allow it to further escalate," Thakur told reporters.
He charged the ULFA, which he said was responsible for most of the recent killings in Assam, were receiving support from a neighbouring country, but did not identify which one.
Assam borders Bangladesh and Bhutan and Indian officials have alleged in the past that separatists cross the borders with both countries.
Bangladesh denies allowing any anti-India fighters to operate from its soil.
Bhutan acknowledges a ULFA presence in its isolated south and has warned it is ready to use force to expel the rebels, who have ignored the Buddhist kingdom's threats.