A U.N. envoy urged Sri Lanka's new government on Tuesday to address skepticism among ethnic Tamils about its efforts to promote post-war reconciliation, saying there should be more progress in accountability and in human rights issues.

U.N. Undersecretary-General for Political Affairs Jeffrey Feltman said the government could improve trust by addressing detentions and disappearances of ethnic Tamils, clarifying the status of land seized by the military, and minimizing the impact of military deployment in the former war zone in northern Sri Lanka.

Feltman spent four days in the island nation, talking with top government officials and activists and visiting Jaffna city in the former war zone.

He is the top U.N. official to visit Sri Lanka since the government came into power in January, defeating former President Mahinda Rajapaksa, who has been criticized for failing to achieve reconciliation and address accountability issues from the civil war that ended in 2009 with the defeat of separatist Tamil Tiger rebels.

President Maithripala Sirisena's government has called reconciliation a priority and promised to release private land occupied by the military during the war and free suspected rebels detained for many years without trial. He also fired a former military official who was the governor of the northern province, replacing him with a civilian.

But Tamil politicians and civilians complain that the government is not moving fast enough.

"When I was in Jaffna yesterday, I heard great skepticism from people in the north about would some of those words really translate into tangible steps that would affect their life," Feltman told reporters.

The U.N. Human Rights Council was scheduled to release a report on war crime allegations against government soldiers and the rebels during the final months of the fighting. But it postponed the release from March until September after the new government requested more time, saying it wants to set up its own judicial mechanism to probe rights violations.

A previous U.N. report said up to 40,000 Tamil civilians may have been killed in just the final months of the fighting. It remains unclear how many people died in the decades-long civil war.

The government has been accused of deliberately shelling civilians and hospitals and blocking food and medicine from getting to people trapped in the war zone. The rebels are accused of forcibly recruiting child soldiers, using civilians as human shields and killing those trying to escape their control.