President Donald Trump is to attend a mass march against abortion in Washington on Friday.

Mr Trump will speak at the March for Life tomorrow, in what will be the first appearance by a sitting president in its 47-year history.

He confirmed his attendance over Twitter, where he shared a video of last year's event and commented 'See you on Friday...Big Crowd!'.

The march was attended by vice president Mike Pence in 2017, and now Mr Trump will take centre stage.

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Organisers say they are 'honoured' to welcome the president, and say he has been a 'consistent champion' for the movement.

"We are deeply honored to welcome President Trump to the 47th annual March for Life," said March for Life president Jeanne Mancini. "He will be the first president in history to attend and we are so excited for him to experience in person how passionate our marchers are about life and protecting the unborn.

"From the appointment of pro-life judges and federal workers, to cutting taxpayer funding for abortions here and abroad, to calling for an end to late-term abortions, President Trump and his Administration have been consistent champions for life and their support for the March for Life has been unwavering.

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"We are grateful for all these pro-life accomplishments and look forward to gaining more victories for life in the future."

Similar marches take place across the world, with the UK version taking to the streets of London on Saturday, June 13.