Sri Lanka has banned 16 Tamil groups in exile, including the Tamil Tigers, for alleged terrorism.
The Colombo government has frozen the assets of the organizations and barred citizens from supporting them or having any contact with them.
Sri Lankan says it is acting under a United Nations Security Council resolution that steps up the fight against terrorism by, among other actions, trying to cut off funding for terror groups.
Tamil Tiger rebels fought a 30 year-long civil war for an independent Tamil state on Sri Lanka.
The United Nations last week approved an international investigation into alleged atrocities and war crimes by Sri Lankan forces during the last years of the war.
The Sri Lankan government has denounced the investigation as politically motivated and one-sided.