By Sanjay Dasgupta
BBC South Asia editor
Media reports in Sri Lanka say that two men arrested in London under Britain's anti-terror laws have suspected connections to the rebel Tamil Tigers.
The Tigers are fighting in the north and east of Sri Lanka
But police in the UK would only say that two unnamed men have been detained on suspicion of providing support to a banned organisation they did not name.
The arrests were made late on Thursday, from two different locations in London.
They are being held under British anti-terror laws which mean they can be held for 14 days without charge.
"Two men, aged 29 and 50, were arrested on 21 June - one in west London and the other in south-west London," said Metropolitan Police spokesman Alastair Campbell.
"They were arrested on suspicion of providing support to a proscribed organisation... and taken to a central London police station, where they remain in custody.
Mr Balasingham was seen as the Tiger's chief ideologue
"Some addresses in various locations in London are being searched in connection with the enquiry."
If the pair are being held for their suspected links to the Tamil Tigers, it will be the first time that people of Sri Lankan Tamil origin have been detained in the UK under the terrorism acts.
Media reports in Sri Lanka say A Krishanthakumar is one of the two men arrested.
He is believed to have been close to the late Anton Balasingham, who was the main spokesperson for the Tamil Tigers in London.
Mr Krishanthakumar accompanied Mr Balasingham and his wife Adel during their last visit to Geneva for peace talks in February 2006.
There has so far been no comment on the arrests from the rebels.
In April, police in Paris arrested more than 16 men for alleged involvement with the Tigers.
Similar arrests were made in the United States last year, when at least five Tamil Tiger sympathisers were arrested and charged in New York with conspiring to buy surface-to-air missiles.
Eleven others were charged with "material support" for the rebel group.