None of the videos have been verified as genuine.
Marie van der Zyl, the vice president of the Board, expressed her “grave concern” that Mr Trump has retweeted a message from the leader of a “nasty far-right group”.
She said: “It is of grave concern that the President of the United States would retweet videos from the deputy leader of Britain First.
Ms Fransen, who was found guilty of religiously aggravated harassment last year, responded by praising Mr Trump in a tweet, adding “GOD BLESS AMERICA!”.
She wrote: “THE PRESIDENT OF THE UNITED STATES, DONALD TRUMP, HAS RETWEETED THREE OF DEPUTY LEADER JAYDA FRANSEN'S TWITTER VIDEOS! DONALD TRUMP HIMSELF HAS RETWEETED THESE VIDEOS AND HAS AROUND 44 MILLION FOLLOWERS! GOD BLESS YOU TRUMP! GOD BLESS AMERICA!”
Update: The White House has defended the President's social media posts, with White House press secretary Sarah Sanders saying, according to CBS: "Whether it's a real video, the threat is real. His goal is to promote strong border security and strong national security."