WASHINGTON (CNN) -- White House communications director Mike Dubke is leaving the administration, he said Tuesday, amid swirling speculation about a possible Trump staff shakeup.

He told CNN Tuesday he submitted his resignation on May 18 but offered to stay until the end of President Donald Trump's foreign trip. A final day has not been set, Dubke said.

"It has been a privilege to serve this president," Dubke said in a phone interview.

Dubke said he had "a good conversation with the President" after submitting his resignation. He declined to discuss the turmoil inside the West Wing, only saying he was resigning "for a number of reasons -- for personal reasons."

Dubke, who founded Crossroads Media, a political admaker based in Alexandria, Virginia, joined the administration in February after he was brought in by Sean Spicer, who served as both press secretary and communications director in the opening days of the Trump administration.

Dubke was a last-minute addition to the administration following the resignation of Jason Miller, who served on Trump's campaign. His appointment came with some criticism, as CNN reported at the time that some inside the White House said they would have preferred a veteran from the campaign.

One Republican strategist described Dubke's job to CNN Tuesday as "impossible," adding, "Mike is a good guy."

Another source close to Dubke said it was likely he will return to the Black Rock Group, a communications firm.