The United Kingdom previously expelled 23 Russian diplomats over the Salisbury incident.
Skripal, a former GRU colonel, who worked for UK intelligence, and his daughter Yulia have been in hospital in a critical condition since March 4 due to exposure to what the UK experts say was a A234 nerve agent. UK Prime Minister Theresa May has accused Russia of orchestrating the attack, and the European Union has expressed its solidarity with the United Kingdom.
Russia, for its part, has strongly rejected the accusations and offered to help in the investigation. However, Moscow's request for samples of the chemical substance used to poison Skripal was rejected.
US President Donald Trump has ordered the expulsion of 60 Russian diplomats, including 48 employees of the Russian Embassy and 12 people who have been assigned to the United Nations in New York, as well as the closure of the Russian Consulate in Seattle, a senior administration official told reporters.
European Council President Donald Tusk also announced that 14 EU countries had decided to expel Russian diplomats over the Salisbury case. Later in the day, two more EU member states announced the same measures.
France, Germany and Poland each expelled four Russian diplomats. Canada also expelled four diplomats.
Czech Republic and Lithuania expelled three Russian diplomats each. The list of countries that expelled two diplomats comprises Albania, Denmark, Italy, the Netherlands and Spain.
Ukraine expelled 13 Russian diplomats.
Iceland announced the suspension of its high-level bilateral dialogue with Russia.
Slovakian Foreign Ministry said it would summon Russian Ambassador Alexei Fedotov on Tuesday to clarify the situation around Russia's alleged involvement in Skripal's poisoning.
Meanwhile, Turkey and Bulgaria announced they would not impose any restrictive measures on Russia.
Russia expresses its strong protest over the expulsion of Russian diplomats from a number of Western countries and will prepare an adequate response, the Russian Foreign Ministry said.
"We express our strong protest in connection with the decision taken by a number of EU and NATO member states to expel Russian diplomats… We consider this step as unfriendly and not serving the tasks and interests of establishing the causes and finding the perpetrators of the incident that took place on March 4 in Salisbury," the ministry said in a statement.
"We deeply regret these decisions," Peskov told reporters, adding that Moscow will apply the principle of reciprocity to this unfriendly move.
He went on to say that the Russian Foreign Ministry and other government bodies will analyze the situation and present their proposals on how to respond to Russian President Vladimir Putin.
"The head of the state will make the final decision," the spokesman said.
Meanwhile, Russian Ambassador to the United States Anatoly Antonov told reporters that Moscow would take an adequate response to Washington's decision to expel Russia's diplomats from the country.
According to Russian Foreign Ministry Spokeswoman Maria Zakharova, "powerful forces" in the United States and the United Kingdom are behind the poisoning of Skripal and his daughter.
"At this point, after all these figures have been published, there is no doubt that strong, powerful forces in the United States and in the United Kingdom stand behind the provocation on the British soil," she said.
Russian Envoy to the UN Vassily Nebenzia called the expulsion of Russian diplomats an "unfortunate and unfriendly move."
"Now, in my opinion, it became absolutely clear that it was not London which invented it [the attack]; the United States came up with this, and everything was ready to do everything that," the diplomat said.
Moscow should respond to the United States' measures — which included the closure of the Russian consulate in Seattle — by closing US consulates in Russia and expelling US diplomats, Lizun suggested.
Washington's decision to expel 12 employees of the Russian mission to the United Nations is illegal, as the organization does not fall under US jurisdiction, First Deputy Chairman of Russia's lower house Committee on Foreign Affairs Vladimir Dzhabarov told Sputnik.
"This violates accepted international norms. The UN is an international organization that is not under US jurisdiction," the lawmaker said.
"This is a conspiracy. The West is disappointed with the [election] results, this level of support shown to Vladimir Vladimirovich Putin by Russian people. So this conspiracy, provocation involving Skripal, was reaching for the opposite. Yet another time, having failed to break Russia’s society, they are trying to attack Russia, its image in international spheres to influence the international community," Chepa told Sputnik.
Trump spoke with many foreign leaders to encourage them to join Washington in expelling Russian diplomats in response to Russia's alleged role in the Sergei Skripal case, White House Deputy Press Secretary Raj Shah said during a press briefing.
Washington's decision will make the United States safer, according to US Ambassador to Russia Jon Huntsman.
"I can’t guess what the Russian government might do. But let me be clear – the United States has taken this action in response to Russia’s attack on our closest ally, the United Kingdom, and its ongoing pattern of destabilizing activities in the United States and elsewhere. We reserve the right to respond further to any Russian retaliation against our entirely justified action today," Olsen said.
Meanwhile, Austrian Chancellor Sebastian Kurz has said Vienna would not expel Russian diplomats over the Skripal case, and would instead work to facilitate a dialogue between East and West.
"Austria supports the clear statement of the European Council and the decision to withdraw the EU Ambassador from Moscow. As a neutral country we will not recall diplomats, moreover, we intend to build a bridge between East and West and keep channels of dialogue with Russia open," Kurz said on Twitter.
The expulsion of Russian diplomats from Italy will mark the final action of the outgoing government under Paolo Gentiloni, which has harmed the country's national interests by catering to the will of foreign powers, head of Italy's right-wing Brothers of Italy (Fratelli d'Italia) party Giorgia Meloni said.
"It is unacceptable that an outgoing government decides to expel two officials of the Russian Embassy. These are the last ditch efforts by a government subdued to the will of foreign states, but thankfully it will soon be put in the conditions not to harm Italian national interests anymore," Meloni said in a statement.
"It's bad news. It is now clear that the West has no intention of extinguishing the fire, which is ignited by the West itself. But, on the contrary, it continues to throw fuel on the fire," Ferrari said.
He went on to note that the expulsion of diplomats accredited to the United Nations was a very serious issue.
"The US should not have jurisdiction over the UN. This is a serious legislative violation. The most correct thing would be for the UN to be moved to Switzerland, a neutral nation," he said.
Thierry Mariani, a member of France's The Republicans party, said he was very disappointed by decision of his country's authorities to expel Russian diplomats.
"I am really disappointed because the countries have chosen to react without any investigation or evidences against Russia. This story looks like a manipulation to me. As a French person, I completely disappointed by the French decision," Mariani told Sputnik on Monday.
The German position on Skripal case, according to head of Die Linke party group of the Quakenbruck parliament Andreas Maure's comment to Sputnik, should not have been determined only by Berlin's solidarity with the European Union.
The moves by Europe and the United States lack integrity, former UK Independence Party (UKIP) parliamentary candidate for Westminster North, Nigel Sussman, told Sputnik.
"My view is that the situation hasn't changed, if anything it has highlighted the coalition of anti-Russian hysteria. The evidence is still not there that Russia had anything to do with this [Salisbury incident]," Sussman told Sputnik.
As each day passes, more information comes to light that Russia had nothing to do with poisoning of the Skripals, he concluded.