Alexey Navalny told CNN it was "absolutely terrifying" to find out he'd been followed for so long. (Photo by CHRISTIAN STREIB/CNN)
CNN  — 

The State Department on Wednesday issued the most decisive statement yet from the Trump administration blaming the Russian Security Service for the poisoning of opposition leader Alexey Navalny, days after CNN reported on the first direct evidence of the agency’s involvement in the poisoning.

“The United States believes that officers from the Russian Federal Security Service (FSB) used a Novichok nerve agent to poison Mr. Navalny. There is no plausible explanation for Mr. Navalny’s poisoning other than Russian government involvement and responsibility,” a State Department spokesperson said. “Of course, President Putin and the Russian government would have us believe otherwise.”

The spokesperson said that Russia’s inability to answer questions about Navalny’s poisoning speaks volumes.

“Russia has suggested numerous, often contradictory, conspiracy theories,” the spokesperson said. “Let’s be clear – these types of conspiracy theories are nothing more than a means to deflect attention from the serious questions before the Russian government, which it has yet to answer.”

The State Department would not explain why the US has not inflicted any cost on Russia for this poisoning or issued a statement sooner. Wednesday’s statement came after repeated requests for comment from CNN.

An investigation by CNN in cooperation with the investigative journalism website Bellingcat revealed that an FSB toxins team of about six to 10 agents trailed Navalny for more than three years before he was poisoned in August with the lethal nerve agent.

That report was followed by the revelation by a Russian agent sent to tail Navalny that they planted the nerve agent in his underpants, a detail that emerged when Navalny called the man and, posing as a member of Russia’s National Security Council, pressed him for details of the operation.

In September, the National Security Council put out a statement saying the US, “will work with allies and the international community to hold those in Russia accountable, wherever the evidence leads, and restrict funds for their malign activities.” Both the United Kingdom and the European Union imposed sanctions on Russian officials for Navalny’s poisoning more than two months ago.

Possible US sanctions have been prepared, according to two sources familiar with the process, but the official rollout requires a whole of government approval which would include sign-off from President Donald Trump, who has never specifically blamed the Russians for Navalny’s poisoning and has tried to downplay suspected Russian responsibility for the recent, massive cyberhack that has affected at least half a dozen government agencies and potentially hundreds of private companies.

Secretary of State Mike Pompeo said in September that there was a “substantial chance” that the Russians were behind Navalny’s poisoning, but the statement issued Wednesday more directly went after Russia, named the FSB and said that the US supports the findings from the investigation by the Organization for the Prohibition of Chemical Weapons (OPCW). It was not issued in Pompeo’s name.

“The United States has full confidence in the OPCW’s findings, which confirmed earlier results from German, French and Swedish labs, that Mr. Navalny was exposed to an unscheduled Novichok nerve agent,” the State Department spokesperson said Wednesday.