This week, the United States resumed deportation flights to Haiti under the public health order. Immigration and Customs Enforcement repatriated about 90 Haitians on Wednesday.

Among those deported were families with young children, according to the Haitian Bridge Alliance, an advocacy group, which also said that they had been expelled under Title 42. Many Haitian families have claimed fear and are not being deported, the official said.

ICE Air uses chartered aircraft that have the capacity to transport about 135 people. The Defense Department is expected to provide some planes as well to transfer migrants to other border stations to ease overcrowding in Del Rio. ICE has flown migrants from the Laughlin Air Force Base in Del Rio to El Paso, Tucson and San Diego for processing.

In recent months, the administration has stepped up deportation flights to Mexico, Central America and South America. In August, there were 99 likely removal flights compared with 46 in July and 35 in June, according to Tom Cartwright, who tracks ICE Air flights for Witness at the Border, an advocacy group.

Haitians represent a small share of border crossers, or about 4 percent of the migrants encountered by border agents in August, dwarfed by Central Americans and Mexicans.

But their numbers have swelled in recent months. Nearly 28,000 Haitians have been intercepted by the Border Patrol along the United States-Mexico border in the current fiscal year, which ends on Sept. 30, compared with 4,395 in 2020 and 2,046 in 2019. Of the nearly 28,000, fewer than 4,000 were turned away under the public health rule, according to the most recent border data, which covers arrests through the end of August.

Despite the public health measure, along some stretches of the border the United States has not been expelling migrant families with young children because Mexico has refused to accept them. And on some days, Mexicans tell border officials that their shelters are at capacity and can take only a certain number of migrants.