GENEVA -- The top UN human rights assembly has approved by consensus a resolution calling for the quick deployment of experts to Burundi to look into abuses amid spiraling violence in the east African country.

After a U.S.-led diplomatic push, the 47-member Human Rights Council -- which counts Burundi among members -- approved the text that calls for the UN human rights chief to send in a mission of experts who are to report regularly on the rights situation there.

The day-long debate Thursday among diplomats and advocacy groups was marked by a defence of Burundi's security forces by a government representative, and teary testimony by Pierre Claver Mbonimpa, a rights advocate who was tortured.

The UN human rights chief, Zeid Raad al-Hussein, told the council that at least 400 people have been killed since April 26, and nearly 3,500 arrested in the political crisis. He said at least 220,000 people have fled the country.