By Jonathan Landay

WASHINGTON (Reuters) - President Donald Trump's foreign aid pause has forced a suspension of flights for more than 40,000 Afghans approved for special U.S. visas and at risk of Taliban retribution, a leading advocate and a U.S. official said on Saturday.

The stoppage was triggered by Trump's order to halt foreign development aid for 90 days pending a review of efficiencies and consistency with his "America First" foreign policy.

Experts and advocacy groups say the foreign aid pause has led to chaos in U.S. and international aid operations and halted nutrition, health, vaccination and other programs.

The order also triggered a suspension by the State Department of funds for groups that help Afghans with Special Immigrant Visas (SIVs) to find housing, schools and jobs in the U.S.

Trump promised an immigration crackdown during his victorious 2024 reelection campaign.

Shawn VanDiver, head of #AfghanEvac, the main coalition of veterans and advocacy groups working with the U.S. government to evacuate and resettle those SIV holders, said he does not believe that the flight suspension was intentional.

"We think it was a mistake," VanDiver said.

He said that he hoped the administration would grant exemptions to the orders for Afghans approved for SIVs because they worked for the U.S government during the 20-year war that ended in the final U.S. troop withdrawal from Afghanistan in August 2021.

"They fought alongside us. They bled alongside us," said VanDiver, who pointed out that tens of thousands of other Afghans are waiting for SIV applications to be processed.

The White House and State Department did not immediately respond to requests for comment.

Reports by the U.N. mission in Afghanistan say the Taliban have detained, tortured and killed former soldiers and officials of the prior U.S.-backed government. The Taliban issued a general amnesty for former troops and government officials and deny the allegations.

The flight suspension has stranded more than 40,000 Afghans, including SIV holders who have been waiting to fly to the U.S. from visa processing centers in Qatar and Albania, said VanDiver and the U.S. official, who spoke on condition of anonymity.

That number also includes Afghans approved for SIVs who have been waiting in Afghanistan and Pakistan to be put on U.S.-funded flights to the Doha and Tirana processing centers to receive their visas, they said.

Nearly 200,000 Afghans have been resettled in the U.S. on SIVs or as refugees since the chaotic 2021 U.S. withdrawal.

In a separate executive order that he signed hours after his inauguration on Monday, Trump suspended all U.S. refugee resettlement programs.

That order resulted in hundreds of Afghan refugees losing their seats on flights, including family members of active-duty Afghan American military personnel, former Afghan soldiers and unaccompanied children.

(Reporting by Jonathan Landay; Editing by Don Durfee and Paul Simao)