Fans of Sally Yates have taken to Twitter using the hashtag #SallyYatesIsAPatriot to demonstrate their support for the former acting attorney general before she testifies in front of a Senate subcommittee.

Ms Yates is expected to reveal that she warned the Trump administration of former National Security Adviser Michael Flynn’s communications with the Russian ambassador almost a month before he resigned.

White House Chief of Staff Reince Priebus and Press Secretary Mr Spicer both asserted that White House counsel investigated Ms Yates’ information and found nothing.

Jeff Sessions presses Sally Yates on her need for independence from the White House

On Twitter, President Donald Trump called on Congress to ask Ms Yates “if she knows how classified information got into the newspapers” – seemingly accusing her of leaking information after talking to the White House.

Several Twitter suggested that Mr Trump’s attacks on Ms Yates were attempts to undermine her credibility, while others said that they can't wait for her "to skewer" the president.