The top U.N. human rights official began discussions with the Sri Lankan government Saturday on the measures taken by the island nation to investigate alleged atrocities committed during its long civil war, as hundreds of protesters marched against the world body's involvement.

The visit by Zeid Raad al-Hussein follows last year's resolution at the U.N. human rights body that required foreign judges to assist Sri Lanka in the investigation.

Sri Lanka's civil war ended in 2009, after the government forces crushed the separatist Tamil Tiger rebels. Both sides were accused of committing grave human rights abuses such as killing civilians and recruiting child soldiers.

Since the end of the war, Sri Lanka has faced heavy criticism for failing to properly investigate alleged war crimes by its forces. Victims' families have been futile in their attempts to seek justice.

Zeid, who arrived early Saturday on a four-day visit, met with Sri Lankan Foreign Minister Mangala Samaraweera. Details on the talks were not immediately released.

During his stay, Zeid will travel to the former war zone and meet victims of human rights violations. He will also talk with top government and military officials, civil activists and religious leaders.

"I will be listening to everything that they have to say and look forward to very constructive discussions in the days to come," Zeid told reporters.

At least 1,000 protesters marched to the U.N. office in Sri Lanka's capital, Colombo, criticizing a report by Zeid last year pointing to horrific abuses, including torture, executions and sexual abuse by security forces, as well as suicide attacks, assassinations and recruitment of child soldiers by rebels.

The report focused on the period between 2002 and 2011.

According to U.N. estimates, at least 80,000 people were killed in the last month of the war, and possibly many more, including up to 40,000 civilians.

Protesters said Zeid's call to involve foreigners in the investigations was aimed at penalizing security forces who fought the rebels and could pave the way for an independent state for ethnic minority Tamils.

"Al-Hussein hands off Sri Lanka; we condemn your report," read a banner carried by the protesters. "No war crimes court, no foreign judges" read another.

In his report, Zeid had called for the creation of a "hybrid special court" that would include foreign judges and investigators, saying Sri Lanka's own courts are not yet ready to carry out a fair judicial process on the atrocities. Sri Lanka says that it will get foreign help, but that foreign judges won't decide cases.