The "Trump effect" has slowed illegal U.S. border crossings. But for how long?

Migrants used to feel that if they reached the United States illegally, they could stay. “They’ve gotten rid of all that,” said Galvez, 36. “I still hope I can go back there. I just don’t know when.”

Trump has credited his tough stance on illegal immigrants for the sharp decline in apprehensions of migrants at the U.S.-Mexico border, tweeting in March that “many are not even trying to come in anymore.” In the first four months of the year, U.S. authorities have detained about 98,000 would-be immigrants heading north, a 40 percent drop from the prior year.

In El Salvador, which has contributed tens of thousands of border crossers in recent years, potential migrants and officials acknowledge that fewer people are heading to the United States. But they say that the slowdown may be temporary — and that the drop-off may not be as large as it seems.

The biggest decline in detentions at the border is for migrants from the Northern Triangle countries — El Salvador, Honduras and Guatemala — according to Kevin McAleenan, acting commissioner of U.S. Customs and Border Protection. Last month, 3,400 people from those countries were apprehended. The previous April, that figure was more than 16,000.