Customs and Border Protection said there were about 133,000 people apprehended at the U.S.-Mexico border in May, more than triple the number in the same month a year ago. In particular, that figure includes a large number of families traveling from Central America through Mexico. The first big test of Trump’s deal will come in July, when CBP updates its data on border apprehensions. “I do not know how high it will go,” McAleenan said Tuesday.

The U.S. is on pace for about 900,000 apprehensions at the border this fiscal year — levels that border officials have said is a crisis that’s straining resources — but the future is difficult to predict. In 2018, migration levels hit a spring peak in May before dipping and rising again in the fall, suggesting this year could also see a June decrease.

“We should expect the number of people crossing the border to drop in the next two months, regardless of the deal, simply because of seasonality,” said Aaron Reichlin-Melnick, a policy analyst at the American Immigration Council. “At this point, it’s far too early to tell whether the deal made any difference.”