Skripal, 66, and his daughter Yulia, 33, remain in critical condition in hospital, nearly three weeks after being poisoned with a nerve agent that British scientists say belongs to Russia’s Cold-War-era chemical stockpiles. Moscow has angrily rejected claims that Skripal, who spied for Britain in the early 2000s, was on a Kremlin-approved hit-list of defectors. But British Prime Minister Theresa May traveled to Brussels on Thursday to brief European Union heads of state about the attack on Skripal.

The summit concluded in the early hours of Friday with the publication of a joint statement, signed by every participating head of state, backing the British claims and expressing outrage at Moscow’s alleged use of a military-grade nerve agent on British soil. The statement said that EU leaders “agree with the United Kingdom government’s assessment that it is highly likely that the Russian Federation is responsible” for the attack on the Skripals. “There is no plausible alternative explanation”, said the statement, and described the attack on the two Russians as a “grave challenge to our shared security”. The statement will be seen as a foreign-policy triumph by London, as Britain has been contacting EU governments seeking from them a direct condemnation of Russia and possible diplomatic actions in response to the alleged attack.

The jointly authored statement also said that the EU would recall its ambassador to Moscow, effective immediately. Markus Ederer, a German diplomat who represents the EU in the Russian capital, will be leaving Russia “for a month of consultations”, in what appears to be a symbolic act of protest by the Europeans. However, some EU members threatened further action and said that they would “coordinate on the consequences to be drawn in the light of” future Russian actions on the matter of the Skripals. In statements made to reporters early on Friday, German Chancellor Angela Merkel said that there may be “further punitive measures” against Russia, adding that they would be coordinated among EU states.

Some media reported that at least five EU member states were considering expelling undeclared Russian intelligence officers from their soil in response to the alleged Russian attack in England. They are said to include France, Lithuania and Poland. The London-based newspaper Daily Telegraph reported that Russia was in danger of having its Western European spy network dismantled in response to the attack on the Skripals. Some EU countries, however, including Italy and Greece, appeared less interested in taking action against Russia. The Greek Prime Minister, Alexis Tsipras, said on Thursday that his government expressed its “solidarity with the United Kingdom”, but that the EU had to investigate what happened in England on March 4.