Southern Baptist Russell Moore is among the leading US evangelical Christians who have today welcomed Donald Trump's reinstatement of the Mexico City Policy that blocks funding to organisations that carry out or promote abortions.

Republicans and some evangelical Christians said it fulfilled Trump's promise to be a pro-life President. 

Russell Moore, president of the Southern Baptist Ethics & Religious Liberty Commission, said: "This decision will save lives, will encourage the hundreds of thousands of men and women who will march on Washington this week for the rights of unborn children, along with millions more around the country who believe that foreign aid should promote life, not end it.

"This is a welcome step in the right direction, and my hope is that the president will continue to defend human dignity and hold the predatory abortion industry accountable."

Alveda King, evangelist and niece of civil rights campaigner Martin Luther King, also praised the new President.

"The die is cast and the path is clear for America to learn that abortion is not health care," the former state representative said.

"Abortion kills babies and all too often harms the wombs, health, psyche and souls of mothers. By reinstating the 'Mexico City Policy' which saves the lives of thousands of babies and women, President Trump is raising the bar for genuine concern for the lives and health of mothers and our children."

Rep. Diane Black, said in a written statement, "With this compassionate executive order, President Trump has turned the page from a sad chapter in his predecessor's legacy and has already started to make good on his promises to the millions of pro-life Americans that helped him ascend to this office."

She praised Trump "for protecting the conscience rights of American taxpayers and prioritizing federal funding for organizations that protect life over those that take it away." 

American taxpayers money has never been used to directly fund abortions by international NGOs as the Helms Amendment, passed in 1973, prohibits the direct use of American funding for terminations.

But the Mexico City Policy goes further in blocking all funding to any organisations that carries out or promotes abortions in their development work, even if US money is not used directly for that purpose.

It was first introduced by Ronald Reagan in 1984 and has become a political football, having been repealed and reinstated by alternative Democratic and Republican presidents ever since. 

The move comes days before hundreds of thousands are expected to demonstrate against abortion in Washington on Friday for the March for Life.

Pictures of Trump signing the executive order surrounded by men on his third day in the Oval Office sparked outrage from women's rights campaigners and Democrats.

Announcing the policy on Monday White House Press Secretary Sean Spicer told reporters at his first daily briefing: "The President, it's no secret, has made it very clear that he's a pro-life president.

"He wants to stand up for all Americans, including the unborn, and I think the reinstatement of this policy is not just something that echoes that value, but respects taxpayer funding as well."