Two child predators and multiple gang members were arrested trying to illegally cross the U.S.-Mexico border within the past week, officials said late Tuesday. 

Rio Grande Valley Sector Border Patrol (RGV) agents working at the Falfurrias Border Patrol Checkpoint on Monday referred a tractor trailer for additional inspection after a K-9 alert. 

A U.S. Border Patrol agent checks cars at the Falfurrias checkpoint, near Falfurrias, Texas.

A U.S. Border Patrol agent checks cars at the Falfurrias checkpoint, near Falfurrias, Texas. (REUTERS/Eric Thayer)

While searching the trailer, officials discovered four illegal immigrants. Among them, was an adult male from El Salvador. Record checks showed that he was convicted in 2020 of sexual assault of a child, U.S. Customs and Border Protection said in a press release

BORDER PATROL NOT USING TITLE 42 TO EXPEL SOME NORTHERN TRIANGLE MIGRANTS AHEAD OF ITS MAY 23 END: SOURCES

Several days prior, Rio Grande City Border Patrol agents arrested a group of nine illegal immigrants. Among them was an adult Guatemalan made. Record checks indicated he had been convicted of sex with a minor less than 16 years old and had served 180 days and three years’ probation, CBP said.

A sign is seen at the Falfurrias U.S. Border Patrol checkpoint near Falfurrias, Texas March 29, 2013.

A sign is seen at the Falfurrias U.S. Border Patrol checkpoint near Falfurrias, Texas March 29, 2013. (REUTERS/Eric Thayer )

RGV agents also arrested an 18th Street and an MS-13 gang member with "extensive arrest records," including unlawfully carrying of a weapon and assault. 

All subjects were processed accordingly. CBP did not respond to a Fox News request for additional details on the arrest by publication time.

Border Security migrant

Immigrant men from many countries are taken into custody by U.S. Border Patrol agents at the U.S.-Mexico border on December 07, 2021 in Yuma, Arizona.  (John Moore/Getty Images)

The arrests come as Border Patrol officials brace for an expected surge in illegal border crossings. President Biden is coming under increasing pressure over the looming expiration of Title 42, a Trump-era public health order that enabled U.S. authorities to turn back most migrants, including people seeking asylum from persecution. 

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CBP data released Monday showed that immigration authorities stopped more than 221,000 illegal immigrants along the Southwest border in March – a 33% increase from February. 

The Associated Press contributed to this report