The US government says it is struggling to deal with a surge of asylum seekers from countries in Central America who travel through Mexico. On Saturday, it cut aid to El Salvador, Guatemala and Honduras - a move Democrats warned would only worsen the situation.

"What we need to do is focus on what's happening in Central America, where three countries are disassembling before our eyes and people are desperately coming to the United States. The president's cutting off aid to these countries will not solve that problem," the No. 2 Senate Democrat, Dick Durbin, told NBC News' "Meet the Press".

He also cast doubt on the viability of shutting the border, describing the threat as "totally unrealistic."

March is on track for 100,000 border apprehensions, Department of Homeland Security officials said, which would be the highest monthly number in more than a decade. Most of those people can remain in the United States while their asylum claims are processed, which can take years because of ballooning immigration court backlogs.

Trump said on Friday he planned to hold a media event at the border in the next two weeks. According to his public schedule, the president will visit Calexico, California, on Friday.

While some Trump critics say he is bluffing, closing the southern border is not unprecedented. Presidents Richard Nixon and Ronald Reagan both shut the border over drug-related issues, while President Lyndon Johnson closed it briefly after the assassination of John F. Kennedy in 1963.

Reuters