About 20 Tamil asylum seekers facing the prospect of being deported from Britain to Sri Lanka have told the BBC that their lives are in danger.
Media reports say that they will be deported from the UK on a chartered flight due to leave London on Thursday.
The UK Foreign Office pressed Sri Lanka on Wednesday to investigate alleged atrocities during its civil war against Tamil rebels.
Britain's Channel 4 showed what it said were extrajudicial killings of Tamils.
Sri Lanka's defence ministry dismissed the videos as fabricated, saying they were intended to discredit the army.
The army defeated the Tamil Tigers in 2009, ending 25 years of war.
Life in jeopardy
British immigration authorities have refused to comment on reports of the deportations.
But the BBC Tamil service managed to speak to a few asylum seekers now detained in camps.
A 30-year-old man - who served with the Tamil Tiger rebels - insisted that his life would be in jeopardy if he was sent back.
The father of a four-year-old child claims to have received threatening phone calls in the UK from pro-government Tamil militant groups.
"If I go back I will be picked up by the Tamil paramilitaries. They will torture me and kill me," the man said.
"If I die here my wife and son will see my body. If I go to Sri Lanka they will not even see my body."
One elderly woman is also among those who were asked to pack their bags.
Human rights groups have criticised the British government over the planned deportations, warning that many could suffer reprisals in Sri Lanka.
Brad Adams, South Asia director of Human Rights Watch, said: "We urge the British government to hold off sending people who could face persecution on return.
"People who are critical of the Sri Lankan government are now often targeted."