The U.S. is "a long way" from taking any "punitive action" against Saudi Arabia over the disappearance of journalist Jamal Khashoggi any time soon, a former ambassador said Monday.

"For President Trump, it is a difficult balancing act," Nicholas Burns, who served under Republican and Democratic administrations as ambassador to the North Atlantic Treaty Organization and Greece, said on CNBC's "Squawk Alley."

"He doesn't want to end the relationship with Saudi Arabia," he added. "But on the other hand, you have American values to uphold."

Burns gave his view on the tensions between Saudi Arabia, Turkey and the U.S. shortly after Trump told reporters that the Saudi journalist, Jamal Khashoggi, may have been murdered by "rogue killers." He added in the same remarks outside the White House that Secretary of State Mike Pompeo would be dispatched to Saudi Arabia that day.

"The president just hasn't been consistent," Burns said.

Turkish officials have reportedly claimed that Khashoggi was murdered by Saudi-backed hit men at the kingdom's consulate in Istanbul.

Khashoggi has been missing since he entered the consulate on Oct. 2. He had publicly criticized Saudi rulers and was living in self-imposed exile in the U.S., but reportedly needed to pick up a document for his wedding at the consulate in Istanbul. Saudi Arabia denies harming Khashoggi, insisting that he left the building shortly after he arrived.

"This is a very serious thing and we're looking at it in a very serious manner," Trump told reporters while traveling in Ohio last week.

But on Monday, Trump announced in a tweet that he had spoken to "the King of Saudi Arabia who denies any knowledge of whatever may have happened 'to our Saudi Arabian citizen.'"

Trump tweet

The president has previously made multiple references to the fact that Khashoggi was not a U.S. citizen, and told reporters on Monday that Saudi King Salman's denial of any knowledge or involvement in Khashoggi's disappearance "could not have been stronger."

Some critics have interpreted those statements as a signal that Trump is reluctant to pursue any form of retaliation against the world's biggest oil exporter.

"The president needs to speak to both sides of the equation," Burns said.

"I hope there will be some punitive action," he added, referring to a letter proffered Wednesday by a bipartisan group of senators that triggered a probe into whether the U.S. should slap sanctions on the kingdom.

"But I think we're a long way from that," Burns said, "because the Saudis aren't likely to come clean on what happened."