These supposed 'welfare camps' lack adequate sanitation facilities and access to clean water,' it added.

The statement, issued on the inaugural UN World Humanitarian Day Aug 19, said heavy rains in the areas of Vavuniya District and Menik Farm have damaged or destroyed up to 1,925 shelters, according to the United Nations Office for the Coordination of Humanitarian Affairs.

The BTF urged international institutions, governments, humanitarian rights groups and humanitarian organisations to help end what it called the 'unprecedented violation of human rights and continuous crimes against humanity' and secure the release of civilians from the camps.

The Sri Lankan government says it needs the camps to screen for fleeing LTTE terrorists.

However, US Assistant Secretary of State Robert Blake has made provision of aid conditional on the resettlement of Tamil refugees and progress on 'reconciliation and devolution of power.'