UN Secretary-General Ban Ki-moon says any credible accusation of human rights violations committed during the final phase of the war against Tamil Tiger separatists in Sri Lanka should be investigated.
Mr Ban said on Friday he would like to ask the Sri Lankan government to recognize the "international call for accountability and full transparency.
Human rights groups have criticized the government for what they say was a disregard for human life during the final months of the war in northeastern Sri Lanka.
Mr Ban and other U.N. officials have also accused the Liberation of Tigers of Tamil Eelam of holding civilians hostage and using them as human shields.
UN officials say it is unclear how many civilians died during the final phase of the war, which ended when the government declared victory over the rebels on 18 May.
The Security Council took no action: UN diplomats say Russia, China and others on the council believe that the war was a domestic issue.