Moscow on Friday announced measures against the 23 countries that have expelled Russian diplomats over the past week.

"On March 30, the Foreign Ministry summoned the heads of diplomatic missions from Australia, Albania, Germany, Denmark, Ireland, Spain, Italy, Canada, Latvia, Lithuania, Macedonia, Moldova, the Netherlands, Norway, Poland, Romania, Ukraine, Finland, France, Croatia, the Czech Republic, Sweden and Estonia," the Russian ministry said in a press release.

According to the ministry, the chiefs of mission were handed notes of protest and told that the Russian Federation was declaring persona non grata the same number of diplomats from each country working in diplomatic missions in Russia in response to their "unjustified expulsions of Russian diplomats based on Britain's proof-free accusations of Russia related to the Skripal case."

The Russian ministry added that as Belgium, Hungary, Georgia and Montenegro had decided to join the aforementioned countries at the last minute, Russia reseved the right to take countermeasures against these countries as well.

Spokespeople from Estonia's Ministry of Foreign Affairs told ERR that Estonian Ambassador to Russia Arti Hilpus was handed a note and informed that Estonian Defense Attaché Col. Toomas Peda would be expelled from the country.

Also among those being expelled are one Latvian and three Lithuanian diplomats.

Estonia among dozens of countries to take steps against Russia

In connection with the March 4 nerve agent attack in Salisbury, Southern England which left ex-Russian spy Sergei Skripal and his daughter Yulia hospitalized, Estonia annouced on Monday that it would be expelling the Military Attaché of the Russian Federation, giving him one week to leave the country.

Minister of Foreign Affairs Sven Mikser (SDE) confirmed that Estonia's decision was part of a coordinated response of EU leaders' March 23 decision regarding Russia's activities and unwillingness to fully cooperate with the U.K. on identifying those responsible for the March 4 nerve agent attack, according to a ministry press release.

"The Salisbury attack is not only a dispute between the U.K. and Russia; it threatens international security and undermines international law," Mikser emphasized. He noted that the nerve agent attack was a serious crime which Estonia has condemned.

"We find it incredibly important to take this deterring step," Mikser said. "It is clear that without a uniform response, such actions will recur."

The Estonian government on Thursday also decided to impose an entry ban on the 49 individuals listed on the so-called Magnitsky List, the names of which were published.

The Latvian and Lithuanian Ministries of Foreign Affairs likewise summoned their respective Russian ambassadors on Monday. Latvia is expelling one diplomat, while Lithuania is expelling three along with imposing an immigration ban against 44 individuals.

The U.S. government also announced on Monday that it would be expelling 60 Russian diplomats from the country and demand that Russia close its consulate in Seattle. Among the 60 diplomats to be expelled are 12 who work at the UN, the BBC reported on Monday afternoon.