The following are diplomatic measures announced against Russia by the United States, Canada, several EU countries, and Ukraine in response to the poisoning of former Russian double agent Sergei Skripal with a military-grade nerve agent in the English town of Salisbury.

Moscow has denied any involvement in the attack.

Britain - Expelled 23 Russians alleged to have worked as spies under diplomatic cover. Promised to freeze any Russian state assets that "may be used to threaten the life or property of UK nationals or residents".

United States - Expelling 60 Russians, including 12 intelligence officers from Russia's mission to UN headquarters in New York. Closing Russian consulate in Seattle.

Canada - Expelling four Russians alleged to have worked as spies or interfered in Canadian affairs under diplomatic cover. Denying three applications for Russian diplomatic staff.

France - Expelling four diplomats

Germany - Expelling four diplomats

Poland - Expelling four diplomats

Italy - Expelling two diplomats

Lithuania - Expelling three diplomats

Czech Republic - Expelling three diplomats

Netherlands - Expelling two diplomats

Denmark - Expelling two diplomats

Latvia - Expelling one diplomat

Estonia - Expelling one diplomat

Finland - Expelling one diplomat

Sweden - Expelling one diplomat

Ukraine - Expelling 13 Russian diplomats

Romania - Expelling one diplomat

Croatia - Expelling one diplomat

Russian response:

Russia has expelled 23 British diplomats and closed the British consulate in St Petersburg and the British Council cultural body.

Russia said on Monday it will respond to all the "unfriendly" moves, but didn't immediately say how.

RIA Novosti news agency quoted an unnamed foreign ministry source as saying: "The response will be symmetrical. We will work on it in the coming days and will respond to every country in turn."