United Nations chief Antonio Guterres urges Americans protesting racial inequities and excessive police force to do so peacefully and calls on US leaders and authorities to listen to them and show restraint, UN spokesperson Stephane Dujarric said on Monday.

Dujarric was responding to a wave of US demonstrations over the death of a black man, George Floyd, in police custody in Minneapolis a week ago. Some of the largely peaceful protests have spiraled into civil unrest in many cities.

“Grievances must be heard, but they must be expressed in peaceful ways and authorities must show restraint in responding to demonstrators,” Dujarric told reporters.

“In the US – as in any other country in the world – diversity is a richness and not a threat, but the success of diverse societies in any country requires a massive investment in social cohesion,” he said.

US President Donald Trump has asked the Justice Department and the FBI investigate the death of Floyd, but has made no major public statement aimed at deescalating the crisis.

He has issued several tweets, describing demonstrators as “thugs” and urging mayors and governors to “get tough” and threatened to use the military against protesters.

On accusations of excessive force by police against protesters, Dujarric said all cases should be investigated.

“We have always said that police forces around the world need to have adequate human rights training, and there also needs to be an investment in social and psychological support for police so they can do their job properly,” he said.