Retired Gen. Stanley McChrystal warned in an interview on Friday that U.S. relations with Saudi Arabia cannot be a "blank check" amid the fallout over the killing of Saudi journalist Jamal Khashoggi.

“I think you have to separate interests out on this. I think if we accept the assumption that the crown prince was involved — and it looks very likely — we have to signal to the world we don’t put up with that," McChrystal told Hill.TV's Krystal Ball and Buck Sexton on "Rising."

“So there have got to be some modifications of our relationship at least with the royal family. We’re going to have relations with Saudi Arabia longterm," he continued. "We should have relations with Saudi Arabia longterm. They are an ally in the region and they are important, but it shouldn’t be a blank check. To any of our partners, there ought to be an understanding that if you violate certain things, there are costs to pay.”

McChrystal's comments come after the Senate, in a rebuke to President Trump Donald John TrumpBiden on Trump's refusal to commit to peaceful transfer of power: 'What country are we in?' Romney: 'Unthinkable and unacceptable' to not commit to peaceful transition of power Two Louisville police officers shot amid Breonna Taylor grand jury protests MORE on Thursday, voted to end support for the Saudi-led war in Yemen.

The resolution came two days after Trump affirmed his support for Saudi Crown Prince Mohammed bin Salman, whom U.S. intelligence officials reportedly believe ordered Khashoggi's murder in October.

McChrystal said he was unsure whether the Senate was taking the right action on Saudi Arabia in regards to the ongoing war in Yemen.

"In terms of Yemen, I'm not sure whether that's the right action to take," McChrystal said. "There's been talk about cutting off arms sales to Saudi Arabia. The reality there is they'll simply buy arms from the Chinese or the Russians. So it's really not in our interests."

— Julia Manchester