Melania Trump's flights to and from the White House before she permanently moved to Washington DC cost the US taxpayer more than $675,000 (£480,000), military records have revealed.

The First Lady made 21 journeys on air force jets in the three months before she moved into the White House in June 2017, the Wall Street Journal (WSJ) reported after reviewing military records.

After her husband's inauguration, she continued to live in Trump Tower, New York City, to allow their son Barron to complete the school year.

During that time, air force jets made at least 19 trips to LaGuardia Airport in New York as well as several to Florida's Palm Beach, the home of Donald Trump's Mar-a-Lago resort.

Before he became president, Trump frequently criticised his predecessor, Barack Obama, and his wife, Michelle, for their trips on air force jets.

In 2012, he hit out at Michelle Obama for going on a ski trip to Colorado, at a reported cost of $83,000.

That included the cost of Secret Service protection, accommodation, flights and other transport, according to the Conservative group Judicial Watch.

Trump weighed in with a series of tweets:

When the White House was asked to comment on the cost of Melania Trump's trips, spokeswoman Stephanie Grisham told the WSJ: "It is no secret that Mrs Trump lived in New York City the first few months of the administration so that her son could finish school.

"The trips mentioned in this story are examples of Mrs Trump juggling dual roles—putting her son first while also fulfilling some of her duties as First Lady."

The president's wife is not the first member of the Trump family to face scrutiny for travel expenses. Tiffany Trump, the president's youngest daughter, took a 10-day summer holiday in Berlin with her boyfriend in the summer at a cost to the US taxpayer of more than $22,000.

In July, it emerged that the Secret Service had to ask for an extra $60m to cover costs while accompanying the Trumps on foreign trips.

Melania Trump Air Force
The First Lady travelled on air force jets at least 21 times in three months Sean Gallup/Getty Images