According to the BBC, Selvarasa Pathmanathan, one of the few Liberation Tigers of Tamil Eelam (LTTE) leaders to survive the military operation, released a statement from an unknown location announcing the formation of the transnational government.
In May, Pathmanathan had acknowledged the Tigers' defeat and claimed that the group had given up violence.
But he is now calling for the next phase of the struggle, and has convened a committee - headed by an exiled Tamil lawyer - to facilitate the formation of the new Tamil government.
Until recently, Pathmanathan served as the LTTE's head of international relations, including financing and arms procurement, reports the Christian Science Monitor.
An opinion piece on TamilNet - a website used by the LTTE to publicize its activities - explains that a transnational government is distinct from a government in exile, as the former comprises representation from across the diaspora, while the latter is aimed at taking control of a specific territory.
It calls the transnational government 'a novel experiment that has no precedence,' and emphasizes the new role of the diaspora in continuing the Tamil struggle.