A number of countries across Europe and North America are expelling Russian diplomats in a co-ordinated response to the nerve agent attack on a former spy in the English city of Salisbury, EU President Donald Tusk said on Monday.

As a direct follow-up to last week's European Council decision to react to Russia within a common framework, already today 14 member states have decided to expel Russian diplomats,\" Tusk told a news conference in Varna, Bulgaria.\"Additional measures including further expulsions are not to be excluded in the coming days and weeks.\"

Tusk's statement came as EU member states were still openly declaring their intention to expel Russian staff and how many staff they plan to expel. The number has since increased from 14.

European countries Norway, Ukraine and Albania, which are not EU members, said they will also expel Russian diplomats.

The US said it is expelling 60 Russian officials, including intelligence agents based in the UN in New York, while Canada will expel four.

The move came after British Prime Minister Theresa May addressed fellow European Union leaders at a summit in Brussels to urge them to support Britain's assessment that Russia was to blame.

The 28 EU states issued a statement saying they agreed it was highly likely Russia was responsible for the poisoning of Sergei Skripal and his daughter Yulia on March 4, and ordered the recall of the bloc's ambassador to Moscow.

TRT World's Tetiana Anderson reports from Washington on the US decision to expel 60 Russians.