The Sri Lankan prime minister Ranil Wickremesinghe attempted to counter criticism of the president's rejection of any international involvement in an accountability mechanism, by stating a foreign role has not been ruled out.
"We have not ruled it out, he has not ruled it out," Mr Wickremesinghe told Channel 4 News following escalating criticism over Mr Sirisena's remarks made to BBC Sinhala last week.
Stating that Sri Lanka was committed to the UN Human Rights council resolution that mandated international involvement in the accountability mechanism, Mr Wickremesinghe however put the onus on the "people".
"Our first prong is the people itself. Whatever else we do they might find also the benefit and that's a long process we have started," he told the British news programme.
"I don't think there is anything to be worried about," he added.
"We are all people who fought for it. I put my neck out more than anyone else and by May all these doubts will go out," Mr Wickremesinghe said.
Repeating remarks made previously, Mr Wickremesinghe expressed doubt over the figure of 40,000 Tamils killed in the last few days of the armed conflict.
"There were large numbers killed, but we have a question mark in this 40,000 but we are interested in finding out the actual number," he said.