Republican Florida Senator Rick Scott has slammed Vice President Kamala Harris and President Joe Biden for "avoiding" the Mexican border, the latest in a series of attacks on the administration for what he has termed a "dangerous national security threat and humanitarian crisis."

The statement comes less than two weeks before Harris plans to travel to both Guatemala and Mexico as part of her plan to use diplomacy to help stem the flow of migrants to the US-Mexican border.

Harris, however, has yet to visit the border since President Biden entrusted her with overseeing US government efforts to work with Mexico and the countries of the Northern Triangle to deal with the rising number of migrants at the border.

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"Flying over the border at 35,000 feet doesn't count as a visit. Now, 123 days since taking office, it's shocking to see the lengths to which President Biden and Vice President Harris will go to avoid seeing the border crisis for themselves," said Scott, who also serves as chair of the National Republican Senatorial Committee.

US government statistics show that more than 178,000 migrants were stopped at the border in April - a 21-year high. The number is slightly more than March's total of 173,000.

"This is about the safety of American families," Scott added. "We must secure the border now." 

US government statistics show that more than 178,000 migrants were stopped at the border in April - a 21-year high. The number is slightly more than March's total of 173,000.

"While I welcome cooperation with Guatemala and Mexico, Biden and Harris have still not acknowledged the humanitarian and national security chaos their policies have created here in America."

Scott alleged that Biden and Harris "still refuse" to go to the border and hear from Customs and Border Protection agents about the situation.

Rick Scott.

"It's time for Harris and Biden to get down to the US border and provide answers to the American people," he added.

Scott's comments are the latest in a series of attacks on the administration about the border.

Earlier in May, for example, Scott said that it is clear "that there is no sense of urgency, responsibility or leadership on border security coming out of the White House."

To pressure the administration, Senator Scott has vowed to hold up every one of Biden's Department of Homeland Security (DHS) nominees.

"If Biden refused to help those risking their lives every day to keep us safe, and put an end to the humanitarian crisis he has recklessly created, I can't allow his nominees to move forward in an expedited fashion," he said in an earlier statement.

Political insiders and experts have repeatedly warned that the role of ‘Border Czar' may leave Harris politically vulnerable.

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"It's a very tough assignment. It's an extremely complex and difficult issue," Michael Shifter, the president of the Washington DC-based Inter-American Dialogue, said in an interview with La Politica Online in April. "It carries risks for her."

The upcoming trip to Guatemala and Mexico marks the Vice President's first during since taking office. She has, however, already spoken twice to both Guatemalan President Alejandro Giammattei and Mexican President Andres Manuel Lopez Obrador.

In early May, Harris noted that an "alarm" number of migrants are choosing to flee conditions in El Salvador, Guatemala and Honduras - a trend she said can only be reversed by addressing issues of systemic corruption in the region.

"No matter how much effort we put in on curbing violence, providing disaster relief, on tackling food insecurity - on any of it - we will not make significant progress if corruption in the region persists," Harris said.