Democrats articles of impeachment very weak: Trump

US President Donald Trump has said the two articles of impeachment charged against him by the opposition Democrats in the House of Representatives are very weak and reiterated that he has done no wrong.

"The Republicans have stuck together there is a witch hunt. It's a terrible thing, but even the democrats they couldn't find very much because they put up two articles that frankly are very weak. They are very weak," Trump told reporters at the White House.

The Democrats charged President Trump with two articles of impeachment, abuse of power and obstruction of Congress by pressing his Ukraine counterpart for help in attacking his rivals in the 2020 election, making him only the third president in American history to face the ignominy.

House Judiciary Committee Chairman Jerry Nadler alleged that Trump, a Republican, was trying to undermine the 2020 election for his own benefit.

The impeachment process was launched after an anonymous whistleblower complained to Congress in September about a July phone call by Trump to Volodymyr Zelensky, the president of Ukraine.

Trump said the Democrats are "very embarrassed" with the articles of impeachment and this is the reason why they agreed to approve his new trade deal to replace NAFTA (North American Free Trade Agreement) with neighbouring Canada and Mexico.

They approved today of all days we have been waiting a year, and they approved today the USMCA and I call that the silver lining to impeachment. Because without the impeachment, they would have never approved it in my opinion," Trump said.

The US, Mexico and Canada signed the deal on Tuesday to finalise their new trade agreement, paving the way to ratification after more than two years of arduous negotiations.