US Secretary of State Mike Pompeo says there are “substantial possibilities” that the suspected poisoning of the Russian opposition figure Alexei Navalny was ordered by senior officials in Moscow.
Mr. Pompeo said the US is considering how they would respond.
NATO and Germany say there is “beyond doubt” that Mr. Navalny was attacked with a Novichok nerve agent.
Pompeo’s comments contrast with President Donald Trump who refused to condemn Moscow.
Mr. Navalny was flown to Berlin from Russia after falling ill on a flight from Siberia to Moscow last month.
The 44-year-old was brought out of an induced coma earlier this week with doctors at Berlin’s Charité hospital saying he was responding to verbal stimuli but that it was “too early to assess the potential long-term effects of his. severe poisoning “.
Mr. Pompeo released his comments in an interview with US conservative commentator Ben Shapiro, who asked if there would be ramifications for the Russian government on apparent attacks on its political opponents.
The secretary of state said the US, together with the EU, made it clear to Russia “our expectations that they hold those responsible for this. We will do our best to come to a conclusion about who was responsible”.
“I think people around the world will see this type of business for what it is,” he added. “And when they see the effort to poison a dissident, they recognize that there is a substantial possibility that this is actually coming from Russia.”
He added that “the world has matured and understood that this is not how normal countries work, and this will prove costly for the Russians.”
Pompeo declined to say how the United States would respond as “I don’t want to stand before the president”, but said Washington would do its part to “reduce the risk of such things happening again.”
President Trump gave no indication of how the United States will respond to the poisoning, saying on Saturday, “I don’t know exactly what happened. I think it’s tragic, it’s terrible, it shouldn’t happen. We haven’t had any. Try yet, but I’ll give. quick View. “
NATO has asked Russia to disclose its Novichok nerve agent program to international monitors. Secretary General Jens Stoltenberg said members are united in condemning the “horrific” attack on Navalny.
On Wednesday, the Russian foreign ministry summoned the German ambassador to protest against what it called “baseless accusations and ultimatums against Russia” and accused Berlin of using the Navalny case “as a pretext to discredit our country”.
Mr. Navalny is an anti-corruption activist who has long been the most prominent face of opposition to President Vladimir Putin in Russia.
His supporters believe his tea was drugged at Tomsk airport on August 20. He fell ill during the flight and the plane made an emergency landing in Omsk to be able to take him to the hospital. Russian officers were persuaded to allow him to be flown to Germany two days later.
A nerve agent from the Novichok group identified by Germany in the Navalny case was also used to poison former spy Sergei Skripal and his daughter in Salisbury, England. Both survived, but a local woman, Dawn Sturgess, died after coming into contact with the poison.
Britain accused Russian military intelligence of carrying out that attack on Salisbury. As part of a coordinated response, 20 countries expelled more than 100 Russian diplomats and spies. Russia has denied any involvement.