Prime Minister David Cameron said London would support an investigation through the UNHRC if Colombo failed to complete an inquiry by the end of March next year.

Britain warned Sri Lanka on Saturday that it could face an international investigation into alleged war crimes committed during the final stages of the country’s civil war, if the government failed to carry out its own probe.

Visiting British Prime Minister David Cameron told reporters at a Commonwealth summit in Colombo that Britain would support an investigation through the U.N. Human Rights Council if the Sri Lankan government failed to complete “a credible, transparent, independent” inquiry by the end of March next year.

Mr. Cameron said that Sri Lanka had great potential for economic development, but needed to move faster to address issues of reconciliation, improve media freedom and address the treatment of people displaced by the conflict.

On Friday, Mr. Cameron visited former Tamil rebel areas in the northern part of the country. He also spoke to journalists from the Uthayan newspaper that had come under regular attack during the government’s war against the Tamil rebels.

He met Sri Lanka’s President Mahinda Rajapaksa later Friday, and said during Saturday’s news conference that “very strong views were expressed on both sides”. Sri Lanka has repeatedly denied allegations that war crimes were committed by the military during the final stages of the conflict against Tamil rebels in 2009.