ANTELOPE WELLS, N.M.— Breaking several hours of radio silence on a cold January night in this remote desert outpost, a Border Patrol agent called out: “There’s a large group about a mile and a half south of the border and heading up.”

Soon after 10 p.m., 247 exhausted men, women and children, most of them families from Central America, walked into view, having trudged for about five hours across the desert on the final leg of a journey to request asylum in the U.S.

Three agents opened the gate of a small forward operating base in anticipation of the group’s arrival. “Walk to my voice,” one shouted in Spanish, as he and others used flashlights to direct the migrants. “We’re right here.”

It had been only a few days since the last large group of Central Americans had crossed the border illegally there. “We’re due,” said one of the agents deployed at one of smallest legal U.S.-Mexico border crossings.

The Trump administration is trying to stop the flow of tens of thousands of families from El Salvador, Guatemala and Honduras that head north each month, fleeing poverty and violence in their home countries. President Trump has also called on Congress to provide $5.7 billion to expand and strengthen a wall on the Mexican border, which fueled the recent government shutdown.