Russia’s foreign minister has insisted his country is “not to blame” for the attempted murder of a former spy on British soil, and has demanded access to samples of the nerve agent used in the attack before cooperating with the investigation. On Monday, U.K. Prime Minister Theresa May declared it “highly likely” that Russia was behind the attempted murder of Sergei Skripal and his daughter, and gave the Kremlin until the end of the day to respond to a demand for “full and complete disclosure” on the nerve-agent program British authorities believe created the poison. Foreign Minister Sergey Lavrov confirmed Tuesday that the British ambassador in Russia has been summoned to the foreign ministry, and has insisted that Russia inspect samples of the nerve agent before helping with Britain’s investigation. Meanwhile, the EU expressed its solidarity with the U.K., despite the fraught relations between the two. “We are very much concerned with the situation, also the findings the U.K. has so far,” European Commission Vice President Valdis Dombrovskis told reporters Tuesday when asked if the EU might back action against Russia. “Of course the U.K. can count on EU solidarity in this regard.” U.S. Secretary of State Rex Tillerson strongly condemned Russia on Monday, but the Trump White House has stayed curiously mum on the escalating situation.