Eight more Russians sent packing from Belgium

"Russia has underestimated the unity of Nato allies," Nato head Jens Stoltenberg said, announcing the move, which came in response to Russia's attempt to kill a former spy in England using a chemical weapon earlier this month.

"It sends a very clear message to Russia that it [its UK attack] has costs," he added.

The Belgian prime minister's office said it was committed to an "open and frank dialogue" with Moscow despite its move.

The Irish leader, Leo Varadkar, said the same day that he had expelled a Russian diplomat despite his country's history of neutrality in European conflicts.

"When it comes to terrorism, assassinations, the use of chemical weapons and cyberterrorism, we are not neutral one bit," he said.

"We are joined with other neutral countries including Finland and Sweden, who have taken the same course of action as us," he added.

Ireland's decision stood in contrast to Austria's, which boycotted the EU expulsions on grounds of neutrality.

Tuesday's expulsions follow more sweeping ones by EU and Nato states on Monday.

They bring to 18 the number of EU states that did so, while nine have opted not to go ahead citing various reasons.

The Belgian move was also quite minimalist, given that it had the power to expel any of the 140 or so Russian diplomats accredited at Russia's Belgian, Nato, and EU missions.

The EU also had the right to take away its accreditation to Russian diplomats in the EU mission.

But both Belgium and the EU opted to leave in place Vladimir Chizhov, Russia's ambassador to the EU, who was tainted with suspicion of espionage activity back in 2009 when Nato expelled his son, Vasily Chizhov, for spying.

Many of the EU and Nato states who expelled Russian diplomats did so on grounds they were expelling spies who posed a security treat.

Many of the Russians accredited as diplomats in Belgium are in fact spies, the then Belgian intelligence chief told EUobserver back in 2012.

The diplomatic expulsions have prompted some surprises.

On Tuesday, the normally Russia-friendly US president Donald Trump called his counterparts in France and Germany and "praised" their tough action on the UK incident.

Slovakia, normally a staunch Nato ally, has refused to expel anyone, prompting its president, Andrei Kiska, to ask the government, also on Tuesday, why it did not "express solidarity with our important ally."

British prime minister Theresa May said the same day the EU ought to consider more "long-term" measures also.

Her comments comes amid debate in the UK, Denmark, and Sweden whether to introduce targeted financial sanctions against Kremlin cronies via so-called Magnitsky Acts, named after a late Russian anti-corruption activist.

The list of EU states who opted for expulsions include: Belgium, Croatia, the Czech Republic, Estonia, Denmark, Finland, France, Germany, Hungary, Ireland, Italy, Latvia, Lithuania, Poland, Romania, Spain, Sweden, and the UK.

Those who did not include: Austria, Bulgaria, Cyprus, Greece, Luxembourg, Portugal, Slovakia, and Slovenia.

Australia, Canada, Macedonia, Moldova, Norway, Ukraine, and the US also joined the EU, covering more than 100 Russians, in what amounted to the largest collective expulsion of its kind in history.