The State Department suspended its refugee program Tuesday night, halting all refugee flights into the United States, under direction of one of President Donald Trump's Day 1 executive orders.

The order initially was set to go into effect on Monday, and its swift implementation surprised and alarmed advocates and nonprofits, leaving some refugees who were already in transit to the U.S. stranded in intermediate countries.

“Travel has been canceled for people who had plans," said Kathie O’Callaghan, the president of Hearts and Homes for Refugees, a nonprofit based in Westchester County, N.Y., that resettles families from around the world. “Many of these families were very close to arriving and will be in limbo.”