US President Donald Trump admitted on Thursday that the impeachment litigation complicated his dealings with overseas counterparts.

He tweeted: "Despite all of the great success that our Country has had over the last 3 years, it makes it much more difficult to deal with foreign leaders (and others) when I am having to constantly defend myself against the Do Nothing Democrats & their bogus Impeachment Scam. Bad for USA!"

​On 18 December, after months of deliberations, the Democratic-dominated House of Representatives voted to impeach Trump on charges of abuse of power and obstruction of Congress. The final say on a motion to remove the president from office will have the Republican-controlled Senate which is expected to review the case early next year.

Trump, who denies any wrongdoing, is the third US president to face an impeachment trial. Neither of the previous two, Andrew Johnson in 1868 and Bill Clinton in 1999 was forced from office. Another president, Richard Nixon, resigned in August 1974 before the House could vote on his impeachment and the Senate could conduct a trial.