WESLACO - A long-held trend changed in the southern border in November.

Mexican nationals are no longer at the top of the list of those detained by Border Patrol for illegal entry.

This was just one of several trends highlighted by a U.S. Customs and Border Protection commissioner during a senate judiciary hearing.

Over 3,000 more Guatemalan than Mexican nationals tried crossing the U.S.-Mexico border in November.

Many are requesting asylum through a system the commissioner described as overwhelmed.

The number of people crossing the border is on the rise. It's not at historic levels, but the makeup changed. 

"To put this in perspective, we will more than double last year's record number of family units at this rate," said CBP Commissioner Kevin McAleenan.

It's different than what CBP saw 10 years ago, said McAleenan before senators.

They built their facilities to handle that type of group.

"Our infrastructure is incompatible with this reality. Our border patrol stations and ports of entry were built to handle mostly male, single adults in custody not families or children," he said.

As a result, they're having to release families quicker.

Repatriation is complicated due to many are from Central American countries.

"The disparate treatment under the Trafficking Victims Protection and Reauthorization Act, still a critical statute, but it allows for children arriving from Mexico and Canada to be repatriated but not from other countries, including those in Central America," said McAleenan.

Senator Richard Durbin pointed out legal avenues, like the Central American Minor program, which allowed children to apply for asylum without making the dangerous trek to the border. The current presidential administration ended it.

McAleenan cautions, of those who end up at the nation's ports, there's still an asylum gap they'll need to clear in the future.

"These weaknesses in our laws now represent the most significant factors impacting border security and they include the asylum gap where approximately 80 percent of individuals meet the initial credible fear bar in the asylum process while only 10 to 20 percent are found to have valid asylum claims at the end of their immigration court proceedings," he said.

According to CBP, only 1.5 percent of families from Central America apprehended in 2017 were repatriated.

The commissioner proposed several solutions like supporting the Central American governments financially to improve quality of life, working with the Mexican administration to address transnational criminal organizations targeting migrants, and investing more on border security including a modern border wall system, technology, and more agents and officers.

To hear the senate judiciary committee hearing in its entirety, you can visit the website.