Colombo: President Mahinda Rajapaksa said Tuesday that defeated "terrorist" elements abroad were defaming Sri Lanka.
His comments at a military academy came less than two weeks after he cancelled an address at the Oxford Union in London because of protests by the Tamil ethnic minority in London.
"Their latest weapon is to defame our country and throw allegations at our war heroes, accusing them of war crimes, Rajapaksa said in Diyatalawa, 160 km east of Colombo.
"We have already commenced the battle against them in the international sphere and are committed to continue it," he said.
Tamil groups in exile are calling for investigations into allegations of war crimes during the final stage of army operations that ended Sri Lanka`s 26-year war against separatist Tamil rebels in May 2009.
The government Friday granted permission for a UN panel to testify before a national commission investigating the war`s final months.
UN Secretary General Ban Ki-moon created the panel to advise him on human rights issues related to Sri Lanka`s military offensive in the northern part of the country.
The government disputes a UN estimate that 7,500 civilians were killed during the final months of the conflict.