The number of migrants apprehended by immigration authorities along the southwest border in June dropped for the first time this year, the Department of Homeland Security said in a statement Tuesday.

The agency said 104,000 migrants were taken into custody over the course of the month, a 28 percent drop from May.

The number of illegal border crossings typically drops in the hotter summer months, but the reduction from May to June of this year outpaced last year’s decline in the same period by 11 percent, according to the agency.

The decline includes decreases in all demographics, including unaccompanied minors, single adults and families.

In a statement, Acting DHS Secretary Kevin K. McAleenan credited work with Mexico and international partners for the reduction.

“We are working with the Government of Mexico to expand Migrant Protection Protocols to allow the U.S. to more effectively assist legitimate asylum-seekers and individuals fleeing persecution and deter migrants with false or meritless claims from making the journey,” McAleenan said.