U.S. Secretary of State Mike Pompeo says there is a “significant possibility” that senior officials in Moscow ordered the poisoning of Russian opposition figure Alexei Navalny.
Mr Pompeo said the US was evaluating how it would respond.
NATO and Germany say there is “beyond doubt” evidence that Mr Navalny was attacked by a Novichok nerve agent.
Mr Pompeo’s comments contradict President Donald Trump, who has refused to condemn Moscow.
Mr Navalny was flown from Russia to Berlin after falling ill on a flight from Siberia to Moscow last month.
Week The 44-year-old was told by doctors at Berlin’s Charita Hospital earlier this week that he was responding to verbal stimuli, but it was too early to estimate the long-term possible effects of his severe poisoning.
Mr. Pompeo is a U.S. citizen. Critic Ben Shapiro made his remarks in an interview with the group, who asked if there would be a formality for the Russian government over the apparent attacks on its political opponents.
The Secretary of State said that the United States, along with the European Union, had made it clear to Russia that “our expectations are that they will hold those responsible accountable. We will do our best to reach a conclusion on who is responsible.”
He added, “I think people around the world will see this kind of activity for what it is.” “And when they see an attempt to poison dissidents, they accept that this is a real chance that this really came from Russia.”
He added that “the world has matured and it is understood that ordinary countries run this way and this will prove costly for the Russians.”
Mr Pompeo declined to say whether the US would respond as “I don’t want to stand up to the president”, but said Washington would play its part in “reducing the risk that such things would happen again”.
President Trump said Saturday that there was no indication of how the United States would react to the poisoning: “I don’t know exactly what happened. I think it’s tragic, it’s terrible, it shouldn’t happen to us.” I don’t have a clue. I’ll still take a look at the evidence. “
NATO has called on Russia to disclose its Novichok Nerve Agent program for international monitoring. Secretary-General Jens Stoltenberg said members were united in their condemnation of the “horrific” attack on Mr Navalny.
On Wednesday, Russia’s foreign ministry called on the German ambassador to protest as “vain accusations and ultimatums against Russia” and accused Berlin of using Navalny’s case “as an excuse to defame our country.”
Mr. Navalny is an anti-corruption campaigner who has long been the most prominent face of opposition to President Vladimir Putin in Russia.
His supporters believe his tea was stolen at Tomsk Airport on August 20. He fell ill during the flight, and the plane made an emergency landing in Omsk so he could be taken to hospital. Russian officials persuaded him two days later to allow him to be taken to the airport in Germany.
The nerve agent of the Novichok group, known in the Navalny case by Germany, was used to poison former spy Sergei Skripal and his daughter in Salisbury, England. They both survived but died after being exposed to poison by a local woman, Don Sturges.
Britain has accused Russia’s military intelligence of carrying out the attack in Salisbury. As part of a coordinated response, 20 countries expelled more than 100 Russian diplomats and spies. Russia denied any involvement.