Despite Russia's repeated denials, France, Germany and the United States have joined the UK in blaming Russia for poisoning an ex-Russian spy. President Trump even went on the record- for the first time- about who he thinks is responsible. CGTN's Roee Ruttenberg has more.

Only after he was asked on Thursday did U.S. President Donald Trump tell journalists: he now believes Moscow is tied to the nerve-agent used to target a former spy on UK soil.

DONALD TRUMP US PRESIDENT "A very sad situation. It certainly looks like the Russians were behind it. Something that should never, ever happen, and we're taking it very seriously, as I think are many others."

Trump's conclusions ... echoing those of his ambassador to the UN ... 24 hours earlier. The President said he spoke by phone with British Prime Minister Theresa May, adding the two were "in deep discussions". Earlier on Thursday, the U.S. and UK -- along with France and Germany -- issued a joint statement calling the apparent poisoning a violation of international law, a threat to security, and an assault on British sovereignty...a position backed by top military brass. The U.S. general serving as head of NATO forces in Europe also told lawmakers in Washington that Russia is carrying out a campaign of destabilization.

CURTIS SCAPARROTTI US ARMY GENERAL, NATO COMMANDER "Russia's increasingly modernized military is operating at levels not seen since the Cold War. At the same time, Russia is using indirect activities to advance its strategic objectives throughout Europe, along its periphery, in the Middle East and beyond, Russia has demonstrated a willingness and capability to use political provocation, spread disinformation and undermine democratic institutions."

That includes elections. On Thursday, the U.S. Treasury slapped sanctions on two dozen Russian individuals and agencies over their alleged meddling in the 2016 vote. This, one month after a special counsel -- investigating foul play -- indicted 13 of them. They include the so-called Internet Research Agency, which American officials believe ran an online trolling operation meant to help then-candidate Trump. And, Yevgeny Prigozhin - a close confidant of Russian President Vladimir Putin. Prigozhin is accused of bankrolling much of the operation. On Thursday, the special counsel, Robert Mueller, reportedly issued subpoenas to the Trump Organization as part of his Russia probe. Critics say the Trump administration waited too long to act.

ANGUS KING US SENATOR "We're never going to be able to get to the bottom of this. We're never going to be able to prevent the Russians from doing again what they did in 2016 until we acknowledge that they did it."

ROEE RUTTENBERG WASHINGTON DC The sanctions also address other "malicious" cyber attacks, including a previously undisclosed U.S. finding that Russia tried to penetrate America's energy grid. And, the NotPetya malware attack last summer, which caused billions of dollars in damage around the world. The U.S. called it the most destructive cyber-attack in history. Roee Ruttenberg, CGTN, in Washington.