Washington DC – Melania Trump said on Monday that her role as first lady has been "the greatest honor of my life" in a farewell message ahead of president Donald Trump leaving office.

"The past four years have been unforgettable," the 50-year-old said in a video message.

She called for caution and "common sense to protect the vulnerable" as the world continues to confront the coronavirus pandemic.

She also asked for support for the Be Best initiative she launched during her time in the White House "to ensure that we as Americans are doing everything we can to take care of the next generation."

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Without specific context, she made a comment that was likely alluding to the storming of the Capitol by the president's supporters earlier this month.

"Be passionate in everything you do but always remember that violence is never the answer and will never be justified," she said.

Last week, the US House of Representatives voted to impeach Trump for inciting the deadly Capitol siege, making him the first president in history to be impeached twice.

He was charged with inciting an insurrection and riling up the mob with his false claims of election fraud.

According to a CNN poll published on Sunday, the approval ratings for Melania Trump are only 42% – the worst figure since she moved into the White House.

The inauguration of President-elect Joe Biden will take place on Wednesday in front of the Capitol in Washington.

Outgoing president Trump has announced he will not take part.