Preparations are under way to refit a Qatari jumbo jet that is expected to serve as Air Force One for President Donald Trump, CBS, the BBC's US news partner, reports.

The Boeing aircraft - valued at $400m (£300m) - is being donated by Qatar as an "unconditional" gift, with any necessary retrofitting costs being borne by the US government.

The deal has ignited criticism from both Trump's detractors and some allies, with a few calling it a "bribe" from a foreign power. 

The White House has insisted that taking the aircraft is legal, and pledged that it will be donated to Trump's presidential library once he leaves office. Current rules suggest US officials can only accept gifts under $480, according to BBC.