The United States is again pressing Sri Lanka to carry out a credible and independent probe into alleged war crimes committed during the country's civil war.

U.S. Assistant Secretary of State Robert Blake on Wednesday urged Sri Lanka's government to address a recent United Nations report citing evidence that Sri Lanka forces killed thousands of civilians in the final phase of the conflict with Tamil Tiger rebels.

The nearly three-decade war ended in May of 2009 with the defeat of the rebels.

U.N. Secretary-General Ban Ki-moon this week sent the U.N. report to the United Nations Human Rights Council in Geneva. The U.N. chief has said he needs a mandate from the council in order to launch an international probe into alleged human rights violations.

Sri Lanka denies any wrongdoing and has initiated its own investigation into the civil war.

Assistant Secretary of State Blake on Wednesday concluded a three-day visit to Sri Lanka, where he met with the president, ethnic Tamil leaders and those living in the former war zone.

Blake said the U.N. secretary-general's sharing of the report with the U.N. Human Rights Council underlines the need for a “comprehensive national reconciliation process.”

The U.S. diplomat also said the process should include credible and independent accounting of those who violated humanitarian law.