The United States said Friday it would refuse entry to Sri Lanka's army chief over "credible" evidence of human rights violations in the bloody 2009 finale to the civil war.

Lieutenant General Shavendra Silva, whose appointment last year drew wide international criticism, will be ineligible to visit the United States, as will his immediate family, Secretary of State Mike Pompeo said.

"The allegations of gross human rights violations against Shavendra Silva, documented by the United Nations and other organizations, are serious and credible," Pompeo said in a statement.

"We urge the Sri Lankan government to promote human rights, hold accountable individuals responsible for war crimes and human rights violations, advance security sector reform, and uphold its other commitments to pursue justice and reconciliation," he said.

Silva was the commanding officer of an army division in the island's northern war-zone in the final months of the military offensive against Tamil Tiger rebels in 2009. Rights groups say some 40,000 ethnic Tamils were killed in mass atrocities as government forces seized Sri Lanka's predominantly Tamil north.

The United Nations, in a report into the allegations, said Silva played a major role in orchestrating war crimes. The 2009 offensive delivered a death blow to the Tamil Tigers, whose nearly four-decade campaign for a separate homeland had killed 100,000 people and was characterized by the rebels' bloody suicide attacks.

Pompeo nonetheless said that the United States hoped to maintain security cooperation with Sri Lanka, which last year was rocked by Easter Sunday bombings by Islamist extremists. "We deeply value our partnership with the Sri Lankan government and the long-standing democratic tradition we share with the Sri Lankan people," Pompeo said. 

Sri Lanka's successive governments have resisted calls for an independent investigation into the conduct of troops during the final months of the conflict.