By VIVIAN SALAMA, Associated Press

WASHINGTON (AP) - A top White House communications staffer has resigned as President Donald Trump considers a major staff overhaul.

The departure of Michael Dubke, Trump's communications director, comes as aides 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's last day has not yet been determined.

A Republican consultant, Dubke joined the White House team in February after campaign aide Jason Miller - Trump's original choice for communications director - withdrew from the White House team. Dubke founded Crossroads Media, a GOP firm that specializes in political advertising.

Dubke is the latest White House staffer to leave this administration as scrutiny intensifies over contacts Trump staffers may have had with Russian government officials during the campaign and transition period.

White House counselor Kellyanne Conway told The Associated Press on Tuesday that Dubke resigned before Trump left for his international trip earlier this month, suggesting that his departure is not linked to any pending shake-ups.

But his departure raises questions about whether previous Trump loyalists are headed to the White House. Trump has entertained formally bringing back his former campaign manager, Corey Lewandowski, and former deputy campaign manager, David Bossie.

Bossie told Fox News' "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 pinned some 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.

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."