The Belarus Foreign Ministry said in a statement that a group of people smeared the facade of the embassy building and then physically assaulted Belarusian diplomats who arrived at the scene. It added that one of the diplomats ``sustained serious injuries requiring urgent medical assistance'' and was diagnosed with a broken nose, a concussion and a broken tooth.

The government said it had summoned a British envoy in Minsk to make a formal protest and demand that those responsible be brought to justice.

Posts on social media show a small demonstration outside the Belarusian Embassy on Sunday. London's Metropolitan Police force had no immediate information on the alleged incident.

Belarus' authoritarian president, Alexander Lukashenko, has unleashed a sweeping crackdown on protesters, journalists and civil society groups since he was reelected in an August 2020 presidential election that the opposition and the West rejected as rigged.