Sri Lanka's ethnic Tamil leaders have asked the top U.N. human rights official to help determine the fate of more than 4,000 civilians reported missing in the country's long civil war amid the new government's assertion that most of them are probably dead.

The U.N. official, Zeid Raad al-Hussein, met Sunday with the chief minister of Sri Lanka's Northern Province, the center of the civil war, which ended in 2009. Zeid is on a four-day visit to Sri Lanka.

Zeid said he discussed several issues with Chief Minister C.V. Wigneswaran, including the missing people, detentions without trial and military-occupied private land. He said he would take the issues up with the central government.

Sri Lankan Prime Minister Ranil Wickremesinghe has said most of those reported missing are probably dead.