U.S. Sen. Jeff Merkley (D-Ore.) says the pee tape is probably real.

President Donald Trump's extraordinary joint press conference with Russian President Vladimir Putin today—in which the American president disparaged the findings of U.S. intelligence that the Kremlin tried to sabotage the 2016 elections—has revived questions about whether Russian agents have blackmailed the president.

In a televised interview with BuzzFeed News this morning, Merkley, Oregon's junior U.S. senator was asked if Putin "has something" to compromise Trump.

"I think it's likely, yeah," Merkley said.

Interviewer Ben Smith asked Merkley to elaborate.

"It's a standard strategy of Russia when people visit there who are important," Merkley said, "to try to get compromising information on them, to set them up with hookers, to tape everything that goes on in their room. So it's likely that they have that."

Smith continued to press the question "Just to put this in the terms that Twitter can relate to: Your view is that the pee tape is real?"

"Something close to that," Merkley replied. "Something close to that."

The tape Merkley is referring to is a much-rumored, unverified video of Trump watching prostitutes urinate on a hotel mattress in Moscow in 2013. That tape was referenced in a dossier about Trump compiled by a former British intelligence agent during the 2016 election.

Merkley, who is publicly weighing a 2020 presidential bid, has become a vocal scourge of the White House this summer. He launched a national outcry over the separation of immigrant families at the U.S. border after he was turned away from a Texas detention center for children.