WASHINGTON — U.S. officials encountered more than 103,000 undocumented immigrants crossing the country's southwest border in March, Homeland Security officials said Tuesday.

The number makes last month a record for March for border crossings since 2007, when more than 115,000 immigrants were stopped at the border.

The officials said crossings by families were at record highs. More than 53,000 people traveling as part of families were apprehended, up from just more than 36,000 in February.

President Donald Trump has threatened to seal the border to stop undocumented immigrants from entering the country. He said at the White House on Tuesday that the United States "has the worst laws of any country in the world" on immigration.

The DHS officials said that Customs and Border Protection is holding more than 13,000 immigrants, and that Immigration and Customs Enforcement, which holds immigrants long term, is at capacity. As a result, hundreds of migrants families are being released to nonprofit organizations or simply dropped off at bus stations.