Boris Johnson has described the death of George Floyd as appalling and inexcusable, following days of protests across the US.
The prime minister made the comments after he was challenged by Labour leader Keir Starmer that he had said nothing nine days after the killing shocked the world.
Mr Johnson replied: "I think what happened in the United States was appalling, it was inexcusable, we all saw it on our screens.”
He said that he understood “people's right to protest what took place”.
But he added: “Though obviously I also believe that protest should take place in a lawful and reasonable way."
He did not respond to Mr Starmer’s call to convey to President Trump the UK's “abhorrence about his response to the events".
Mr Johnson also said he was “happy to look into any complaints” about the use of UK exports.
Labour has called for a ban on riot control exports to the US, amid scenes of excessive force being used against protesters.
The party said the UK had licensed exports of riot shields and tear gas in the past year and use for internal repression would contravene the law.
Mr Johnson added that the UK already has “possibly the most scrupulous” review process of any country in the world.
Meanwhile, the UK's most senior police officer has said she was "appalled" by the death in Minnesota and "horrified" by the violence across US cities.
Metropolitan Police Commissioner Dame Cressida Dick told the London Assembly police and crime committee: "Like everybody, we have been appalled by the images we saw of George Floyd and the way he apparently lost his life and we know that justice and accountability must follow and will follow, I'm sure.
"We are also horrified, sitting here in London, as most people, at the violence and destruction that is going on in so many cities in the States in the last few days. And our hearts go out to everybody who's been affected by that."
She told London assembly members: "I recognise, also, feelings are running higher in London" due to events in the US, as well as the coronavirus crisis.
Dame Cressida added: "I do want to reassure people in London... that we will continue with our tradition of policing, using minimum force necessary, working as closely as we possibly can with our communities.
"Met officers and staff are highly professional, they're very well trained, they're very restrained and they're also very, very highly scrutinised, something we don't flinch from at all."
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