The flow of migrants at the southern border surged in May as authorities last month apprehended or deemed inadmissible for entry more than 144,000 migrants, according to numbers released Wednesday by U.S. Customs and Border Protection. The tally is a 32 percent jump from April and includes the highest number of apprehensions in a month on the southern border in 13 years .

More than 55,000 migrant children were among those taken into custody while the number of families and unaccompanied migrant children encountered at the border skyrockets, officials told reporters.

The volume of migrants has taxed immigration facilities beyond their breaking point. CBP is currently housing some 19,000 migrant detainees, more than three times beyond what authorities consider a crisis level, officials said.

"We are in a full-blown emergency. I cannot say this stronger: the system is broken," acting CBP Commissioner John Sanders said.

Family unit apprehensions jumped dramatically last month, continuing a trend: Border Patrol apprehended some 84,500 migrants in family units in May, a 44% increase over the number of families caught at the border in April and more than triple the number of those apprehended in November. An additional 4,134 migrants together as families appeared at ports of entry, but were deemed inadmissible by authorities.

The number of unaccompanied migrant children also rose in May, increasing to about 11,500 from 8,900 in April.

Sanders noted that nearly 680,000 people have been encountered so far this year on the southern border – more than the population of Miami and on pace to break records for the number of migrants encountered in a year, he said.

Officials said most of the migrants arrests at the border are from Honduras, Guatemala and El Salvador – a group of Central American countries commonly known as the Northern Triangle.

The volume of people arriving at the border has strained immigration facilities "beyond the breaking point," said Randy Howe, CBP's executive director of operations in the office of field operations.

A report from the Department of Homeland Security watchdog found "dangerous overcrowding" at a Border Patrol processing center in El Paso, Texas, in May, where cells were stuffed with 5 to 6 times the number of migrants than were their capacities.

To handle the number of migrants, Customs and Border Patrol agents from all over the U.S. have been pulled from their posts to help at the southern border. Pooling resources at the southern border will impact operations elsewhere and increase wait times at ports of entry, especially as the summer travel season picks up, officials said.

In addition to seeing the demographic of migrants encountered at the border shift dramatically from mostly single adults to primarily families and unaccompanied children, immigration authorities said they are also seeing a marked increase in the number of large groups apprehended along the border.

Authorities have encountered 182 groups of 100 migrants or more this fiscal year, including 48 in May, officials said. Last year, Border Patrol encountered 13 such groups.

Last week, a group of over 1,000 migrants surrendered to Border Patrol agents after crossing the border illegally. It was the largest group Border Patrol has ever seen, officials said.

The influx of migrants has been a constant focus of President Donald Trump, who has previously declared a national emergency to build a border wall and purged the leadership of the Department of Homeland Security, vowing to get "tougher" on immigration.

Last week, Trump announced that the U.S. will impose tariffs on Mexican goods in an attempt to compel Mexico to stymie the flow of migrants arriving at the U.S.-Mexico border. Mexican and U.S. officials were meeting Wednesday for talks over the tariffs, which have been unpopular even among Republican lawmakers.

