The Trump administration is vastly expanding the scope of a policy blocking US assistance to foreign groups that perform or provide information about abortions, a move critics say will hinder women's access to critical care.
The new policy means that $US8.8 billion ($A11.9 billion) in US assistance to an array of programs fighting HIV/AIDS, malaria and maternal and child health will be subject to the so-called Mexico City policy.
The policy, introduced in 1984, holds that no US government funding for family planning services can be given to foreign clinics or groups that offer abortion services or discuss abortion, even if the funds for those activities come from non-US government sources.
The policy previously applied to a much narrower stream of about $US600 million in US government funds.
Since it was unveiled, the Mexico City rule has been routinely rescinded under Democratic administrations and reinstated under Republican ones, and is used by presidents to signal where they stand on abortion rights.
Critics of the policy call it the "global gag rule," and say it hurts vulnerable women worldwide who depend on aid groups for their healthcare.
President Donald Trump, a Republican, reinstated the policy in January, just days after taking office, but he went further and directed government agencies to figure out a plan to apply the policy "to global health assistance furnished by all departments or agencies".
US Secretary of State Rex Tillerson has approved a plan to expand the policy's provisions to funding for HIV/AIDS, maternal and child health, malaria and other health programs, the State Department said on Monday.
That includes about $US6 billion in funding for the President's Emergency Plan for AIDS Relief, or PEPFAR, the world's largest provider of AIDS-fighting medicine.
Other programs affected by the expanded policy, called "Protecting Life in Global Health Assistance", include the President's Malaria Initiative, which received about $US621 million in funding in 2016, according to its website.
US officials said the malaria and HIV/AIDS programs would be resilient even if the United States had to deny funding to existing healthcare providers.
The new policy applies to funds provided to foreign non-governmental organisations, but not to aid provided to governments or multilateral organisations, the State Department said. The expanded policy also does not apply to humanitarian assistance and disaster relief or to UN funds and programs.
Democratic Senator Jeanne Shaheen, who sits on the Senate Foreign Relations Committee, said the expanded policy would have "severe consequences for millions of vulnerable women and children."
Anti-abortion groups praised the decision, saying it merely represented a realignment of funding.
