The departure of Michael Dubke, Trump's communications director, comes as aides and outside advisers say Trump has grown increasingly frustrated by allegations of Russian meddling in the 2016 election and revelations of possible ties between his campaign and Moscow.
Trump tweeted Tuesday: "Russian officials must be laughing at the U.S. & how a lame excuse for why the Dems lost the election has taken over the Fake News."
Dubke wrote in a statement that it had been an honor to serve Trump and "my distinct pleasure to work side by side, day by day with the staff of the communications and press departments."
Dubke offered his resignation earlier this month, White House counselor Kellyanne Conway told The Associated Press on Tuesday, but offered to stay on during the president's first foreign trip. His last day has not yet been determined.
White House chief of staff Reince Priebus thanked Dubke in a statement and said Dubke had "offered to remain onboard until a transition is concluded."
"Mike will assist with the transition and be a strong advocate for the president and the president's policies moving forward," he said.
A Republican consultant, Dubke joined the White House team in February. The position had gone unfilled after campaign aide Jason Miller — Trump's original choice for communications director — backed out of the job in December before the president's inauguration. Dubke founded Crossroads Media, a GOP firm that specializes in political advertising.
Dubke is the latest White House staffer to leave the administration as scrutiny intensifies over contacts Trump staffers may have had with Russian government officials during the campaign and transition.
It's unclear whether other staff moves are imminent. Trump has entertained bringing his former campaign manager, Corey Lewandowski, and former deputy campaign manager, David Bossie, more formally back into the fold. And both Lewandowski and Bossie visited the White House on Monday night, according to a person familiar with the meeting, who spoke on condition of anonymity to discuss a private get-together.
Bossie told "Fox & Friends" that the Trump administration has reached out to him but hasn't offered him a job yet.
"They have talked to many people, including me," Bossie said. He later added: "It's an ongoing conversation, and that's a fair way to put it."
In an interview on Fox News on Tuesday, Conway said Dubke "made very clear that he would see through the president's international trip, and come to work every day and work hard even through that trip because there was much to do here back at the White House."
Dubke's hiring was intended to lighten the load on Sean Spicer, the White House press secretary, who had also been handling the duties of communications director during Trump's first month in office. Trump has privately and publicly pinned much of the blame for his administration's rough start on the White House's communications strategy.
While overseas, Trump's longtime lawyer, Marc Kasowitz, joined a still-forming legal team to help the president shoulder the intensifying investigations into Russian interference in the election and his associates' potential involvement. More attorneys with deep experience in Washington investigations are expected to be added, along with crisis communication experts, to help the White House in the weeks ahead.
The latest revelations to emerge last week involved Trump's son-in-law and top aide, Jared Kushner. Shortly after the election, Kushner allegedly discussed setting up a secret communications channel with the Russian government to facilitate sensitive discussions about the conflict in Syria.
The intent was to connect Trump's chief national security adviser at the time, Michael Flynn, with Russian military leaders, a person familiar with the discussions told the AP. The person wasn't authorized to publicly discuss private policy deliberations and insisted on anonymity.
Flynn handed in his resignation in February after it was revealed he misled top White House officials about his contacts with Russian officials.
A senior administration official said Kushner was keeping his head down and focusing on work after the foreign trip. The official said Kushner was eager to share what he knows with Congress and other investigators. The official was not authorized to publicly discuss private thinking and spoke on the condition of anonymity.
The disclosure of the back channel has put the White House on the defensive. Just back from his nine-day trip to the Middle East and Europe, Trump dismissed recent reports as "fake news."
Trump also has renewed his criticism of Germany following Chancellor Angela Merkel's suggestion that her country needs to adopt a more independent stance in world affairs.
Trump posted a tweet Tuesday saying "we have a MASSIVE trade deficit with Germany, plus they pay FAR LESS than they should on NATO & military. Very bad for U.S. This will change."
Associated Press writers Catherine Lucey and Jill Colvin contributed to this report.