Washington - 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 on Tuesday: "Russian officials must be laughing at the US & how a lame excuse for why the Dems lost the election has taken over the Fake News".Scrutiny intensifiesDubke wrote in a statement that it had been an honour to serve Trump and "my distinct pleasure to work side-by-side, day-by-day with the staff of the communications and press departments".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 specialises 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 counsellor Kellyanne Conway said 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.Talking to manyBut 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".