SAN DIEGO — U.S. authorities say border arrests fell 18 percent in June from a month earlier to the lowest levels since February.
Customs and Border Protection said Thursday that it made about 42,600 arrests in June compared with nearly 52,000 in May. That's still nearly double the number in June 2017.
It is unclear what drove the decline. Seasonal trends may be a big influence as scorching, potentially lethal heat deters crossers. President Donald Trump's "zero-tolerance" policy, which resulted in separation of hundreds of families, may also be a driver.
The Border Patrol, which polices between ports of entry, made about 34,000 arrests. The rest occurred at official border crossings.
More than 4 of 10 Border Patrol arrests were of people who came as families or children traveling alone.