WASHINGTON ― President Donald Trump aided Moscow’s disinformation campaign during the 2016 U.S. election by spreading false information originating from Russian state-sponsored news outlets and internet bots, a cybersecurity expert testified before Congress on Thursday.

“Part of the reason active measures have worked in this U.S. election is because the commander in chief has used Russian active measures, at times, against his opponents,” Clint Watts, a fellow at the Foreign Policy Research Institute, told members of the Senate intelligence committee during the panel’s first public hearing on Russian election interference since Trump’s inauguration in January.

The charge from Watts, a former FBI Special Agent who tracks Russian influence operations, came in response to a question from Republican Sen. James Lankford (Okla.), who asked why Russian President Vladimir Putin believed he could get away with interfering in last year’s U.S. elections.

“They parrot the same lines,” Watts responded, referring to Trump and Moscow. “[Trump] denies the intel from the United States about Russia. He claimed that the election could be rigged. That was the No. 1 theme pushed by RT, Sputnik news,” Watts continued. “He’s made claims of voter fraud, that President Obama is not a citizen, that … Congressman Cruz is not a citizen.”

In some instances, Trump and his campaign team propagated fake stories they appear to have learned about directly from Russian state media. Last year, then-campaign chairman Paul Manafort accused the U.S. media of failing to cover a terrorist attack against the NATO air base in Incirlik, Turkey. There was no such attack ― but RT, Sputnik and pro-Russian Twitter accounts pushed a series of stories suggesting Incirlik was under threat.

According to Watts, pro-Russian Twitter accounts noticed Trump’s loose relationship with facts and sought to capitalize on it. They “tweet at President Trump during high volumes when they know he’s online and they push conspiracy theories,” Watts testified.

The U.S. intelligence community released a public assessment in January concluding that the Russian government used a campaign of false information and cyber hacking efforts to discredit Democratic candidate Hillary Clinton and help Trump win the 2016 election. There is an ongoing FBI-led investigation into Moscow’s alleged efforts and possible collusion with the Trump team. The House and Senate intelligence committees are conducting their own separate probes into the matter.

While the Kremlin appeared to favor Trump in the 2016 presidential election, there are indications that Moscow has sought to undermine Republican politicians as well, Watts said Thursday. During the presidential primary races, Russian media outlets “sought to sideline opponents on both sides of the political spectrum with adversarial views towards the Kremlin,” Watts said.

Turning his gaze toward Sen. Marco Rubio (R-Fla.), a committee member and a GOP presidential candidate last year, Watts said, “Senator Rubio, in my opinion you, anecdotally, suffered from these efforts.”

This past week, Watts continued, social media accounts pushed material discrediting Speaker of the House Paul Ryan (R-Wis).

AshLee Strong, a Ryan spokeswoman, said she wasn’t familiar with the activity mentioned by Watts but added that it was unsurprising “that foreign adversaries are trying to undermine our efforts.”

Rubio, who did not immediately respond to Watts’ claim, later confirmed that former members of his presidential campaign team were targeted by IP addresses that traced back to an unknown location within Russia. According to Rubio, the attempted breaches occurred in July 2016, shortly after he announced he would run for Senate re-election, and again this week, at 10:45 a.m. on Wednesday. Both attempts were unsuccessful, he said.

It’s likely Moscow will turn against Trump as it becomes politically and strategically prudent to do so, Watts warned. “They win because they play both sides,” he said.

Russia began developing its active measures campaign in 2009, with its capabilities progressing all the way up until the 2016 election, Watts said. The U.S. was slow to catch on to the threat, he charged, because the intelligence community has been “over-focused on terrorism” and biased against open-source information.

“My two colleagues and I use three laptops and we do this at our house,” Watts said. “But for some reason, the entire intel apparatus, with billions of dollars, will miss a tweet or a Facebook post that’s right in front of them.”

This story has been updated to include comment from Ryan’s office.