A man of Tamil origin committed suicide outside the United Nations' Geneva office by setting himself on fire, UN officials and the police confirmed Friday, dpa reported.
The suicide took place the night before, the officials said, adding that there was no security threat to the UN.
Members of the Tamil community in Switzerland said the man came from abroad to commit the act.
"The man's name is Murukathasan. He came here from the UK," said Shan, who lives in Bern the Swiss Capital and was in Geneva to take part in the protest. Many Tamils use only one name.
Shan added that the man left a note, now in police custody, and sent a notice to Tamil media networks saying he was protesting the plight of his people, for which he blamed the Sri Lankan government and military.
The Tamils said several people in Asia have committed similar acts in recent days, in signs of solidarity with the rebel Tigers, but that this was the first one they knew of in Europe.
Several hundred people congregated late Friday on the spot where the man burned himself to protest the ongoing military campaign in Sri Lanka. Some placed flowers and lit candles near the suicide spot, now covered in sand.
The protest was already planned but the death sparked further anger among the demonstrators, who said the Sri Lankan government was waging a campaign against Tamils as a people and not only against the rebels, the stated target.
Some demonstrators wore rebel Tiger scarfs and Palestinian kafiyas and shouted slogans against the military offensive.
Last week, thousands of Tamils gathered outside the UN to protest the ongoing conflict in Sri Lanka and asking the world body for humanitarian assistance.
Tamil rebels have been pushed into an area of less than 150 square kilometres in what is seen as the last phase of a long military battle against the Liberation Tigers of Tamil Eelam (LTTE).
The rebels have been fighting for the past 25 years for an independent homeland for the Tamil ethnic minority in the northern and eastern provinces of majority-Sinhalese Sri Lanka, but the rebels have lost almost all their territory in the military drive launched in August 2006.