The number of undocumented immigrant family units apprehended last month along the U.S. border with Mexico spiked by nearly 40 percent compared to July, the Department of Homeland Security announced Wednesday.

About 12,800 family units were apprehended on the border in August, a 38 percent increase from July’s 9,247. In a statement, DHS spokesperson Tyler Q. Houlton attributed the spike, in part, to smugglers and traffickers exploiting immigration laws.

“Smugglers and traffickers understand our broken immigration laws better than most and know that if a family unit illegally enters the U.S. they are likely to be released into the interior,” he said.

The most active areas for the unauthorized crossings continue to be Texas’ Rio Grande Valley and El Paso sectors. Last month, about 7,100 family units and 2,235 unaccompanied minors were apprehended in the Rio Grande Valley. In the El Paso sector, which includes New Mexico, there were about 1,885 family units and 530 unaccompanied minors apprehended. All of those stats indicate significant increases from July. That month about 5,215 family units and 1,930 unaccompanied minors were apprehended in the Rio Grande Valley sector, while El Paso saw about 1430 and 425 unaccompanied minors.

The number of unaccompanied minors apprehended over the entire southwest border dipped, however. In July 5,920 were apprehended, compared to about 4,400 last month.

The statistics were released one day after the federal Health and Human Services agency announced it was keeping the detention facility in Tornillo open until at least the end of the current calendar year. The facility bed space will also expand from its current 400 to 3,800.

This article originally appeared in The Texas Tribune at The Texas Tribune is a nonprofit, nonpartisan media organization that informs Texans — and engages with them — about public policy, politics, government and statewide issues.