PORT-AU-PRINCE, Haiti — The Haitian migrants had done well for themselves. Since leaving their country, many more than a decade ago, they had built lives in Chile, Brazil, Panama. They had homes and cars. They had stable jobs as bank tellers, welders, mine supervisors, gas station attendants.

But they longed for the possibility of a better life in the United States, under a president who had protected Haitians in the United States from deportation and many believed would relax entry requirements. So they sold their belongings, left their jobs and pulled their kids out of school. And they headed north.

But instead of the reception they’d expected, they were detained in the small border town of Del Rio, Texas, and without warning deported — to Haiti, a broken country many no longer recognized — in a head-spinning sequence that left them feeling mistreated and betrayed.

Some said they never talked to an immigration agent. Others said they’d been tricked — told they were being released or sent to Florida, and instead packed on a plane to Port-au-Prince, where they landed on Sunday, some in hand and ankle cuffs after protesting.

“They treated us terribly,” said Nicodeme Vyles, 45, who had been living in Panama since 2003, working as a welder and carpenter.

Mr. Vyles and about 300 other Haitians who landed on Sunday were the first among some 14,000 migrants who authorities in the country expect over the next three weeks.

As the first three flights arrived, Haitian officials beseeched the United States to grant a “humanitarian moratorium,” as their country reels from the assassination of its president in July and a powerful earthquake in August.

But the Biden administration, facing the highest level of border crossings in decades, has enforced policies intended to slow the entry of migrants. The Haitian deportations are consistent with those policies, officials said this weekend.

Alejandro N. Mayorkas, the secretary of the U.S. Department of Homeland Security, said on Monday that while the United States has extended protection for Haitians who had arrived in the country before July 29, those who arrive now are not covered.

“We are very concerned that Haitians who are taking this irregular migration path are receiving false information that the border is open or that temporary protected status is available,” he said during a news conference in Del Rio, where thousands of Haitians have been camped out.

“Trying to enter the United States illegally is not worth the tragedy, the money or the effort,” he added.