Trump threatens to close the U.S.-Mexico border next week: 'I'm not playing games'

President Donald Trump on Friday threatened to close the U.S-Mexico border next week if Mexico does not stop undocumented immigrants from coming into the United States, later adding that he's "not playing games" with his warning.

But a senior administration official undermined the president's threat, saying the Department of Homeland Security has no plans to close the border next week.

Trump, while speaking to reporters at an event at Lake Okeechobee in Florida, accused Mexico of choosing not to stop migrants coming to the U.S. southern border.

"If they don't stop them, we are closing the border," Trump said. "We will close it and keep it closed for a long time."

"I'm not playing games," he added.