The United States and its European allies are expelling dozens of Russian diplomats in a co-ordinated response to the poisoning of a former Russian spy in the UK.
President Donald Trump’s move is the largest expulsion of Russian intelligence officers in US history.
Germany, France, Ukraine, Canada and various European countries have also expelled envoys.
Russia vowed to retaliate to the “provocative gesture”.
Russia denies any role in the attack on Sergei Skripal and his daughter, Yulia, in Salisbury, southern England. The pair remain in a critical but stable condition in hospital.
EU leaders agreed last week it was highly likely Russia was behind the nerve-agent poisoning.
The US has ordered 60 envoys to leave, and diplomats are also being expelled from 14 EU countries – alongside the UK which already made the move last month.
British Prime Minister Theresa May said the show of solidarity gave a strong message.
“We welcome today’s actions by our allies, which clearly demonstrate that we all stand shoulder to shoulder in sending the strongest signal to Russia that it cannot continue to flout international law,” a statement from Mrs May’s office said.
Foreign Secretary Boris Johnson said the “extraordinary international response by our allies stands in history as the largest collective expulsion of Russian intelligence officers ever”.
Remarkable show of solidarity
By Jonathan Marcus, BBC diplomatic correspondent
This is building into the most serious diplomatic crisis between Russia and the West since Moscow’s seizure of Crimea.
Whatever the denials, Britain’s allies have clearly accepted its view that the use of a military grade nerve agent in Salisbury was “highly likely” the work of the Russian state.
The collective expulsions from the US and 14 EU member states is a remarkable show of solidarity with Britain, even more so because it comes at a time when UK-EU relations are strained due to the Brexit negotiations.
Donald Tusk’s note that there could be “additional measures” is a signal to Moscow as it considers how it will respond.
It is a significant diplomatic victory for Prime Minister Theresa May – concerted action has now followed the strong rhetorical support from its allies. It also marks a significant toughening of the Trump administration’s stance towards Moscow.
BBC