A Democratic lawmaker said Thursday that Republican lawmakers have begun to separate themselves from President Donald Trump.

Sen. Jeff Merkley (D-OR) told CNN anchors Wolf Blitzer and Pamela Brown that Republicans have voiced their concerns over the president's recent moves and have questions about Defense Secretary Pete Hegseth's most recent comments on the Sept. 2 strike on an alleged drug boat in the Caribbean, off the coast of Venezuela.

Merkley, who serves on the Foreign Relations Committee, argued that the administration's response to the killings is not a satisfactory response for him. He described what the lawmakers have learned about the second strike, where "two helpless men clinging to debris" were killed.

"If this was a legal action of war, which is still under dispute, then it would be a war crime," Merkley said. "If it was not, it was a murder. In either case."

The Democratic lawmaker said that the U.S. Coast Guard should have investigated this incident.

"Again, the right way to find out if there are drugs aboard a boat is you stop the boat, you board it, you investigate it, and in the process you learn if there are drugs, you learn about the strategies involved, which gives you information to help dismantle a broader operation," Merkley said. "Blowing a boat up, not even knowing much about what the boat is doing simply destroys that type of information. So it's not only extrajudicial, it is also stupid. And so this is this is vast concerns about judgment. And by the way, of course, this is all a prelude to the possible strikes on Venezuela itself."

Trump has signaled that the U.S. has planned to attack Venezuela in ground strikes, although those details have not yet been released publicly.

The recent revelations have prompted congressional leaders to request Admiral Frank M. “Mitch” Bradley brief lawmakers Thursday in Washington, D.C. It has also raised questions about whether GOP leaders are ready to face the president over the reports, among other lingering concerns.

“There has been such a sense, of my colleagues, that they are not ready to confront Trump over the mistakes of this administration but we have started to see cracks in that following the November election a month ago where they're starting to feel like they have hitched their wagon to a horse that is going to take them over a cliff and they better start separating themselves,” Merkley said.

Merkley said it will be interesting to see what Republicans say after the briefings Thursday and that he believes Hegseth should resign.

“My Republican colleagues in the Senate are getting very nervous about being tied — not just to Hegseth — but to the overall actions of the administration," he added.