MCALLEN, Texas – America's drug czar, touring a border area beset by increased shipments of illegal drugs, told Fox News in an exclusive interview Wednesday that officials there were stretched so thin they "have no ability to really focus in on the core mission."

In a double-pronged challenge, border patrol officials in the Rio Grande Valley region of south Texas are reporting an increase in cocaine and methamphetamine seizures, while border patrol agents are also struggling to manage a large number of migrants crossing the border illegally.

“They are stretched incredibly thin, they’re trying to help people survive the journey but they have no ability to really focus in on the core mission about finding out what is coming into this country,” said Jim Carroll, director of the Office of National Drug Control Policy, during an exclusive interview with FOX News at the southern border.

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Carroll, who was confirmed by the Senate in January, saw firsthand areas where border patrol agents reported seizing large amounts of illegal drugs, weapons, and cash.

The U.S. Border Patrol provided FOX an in-depth look at how it patrols areas where officials said Mexican drug cartels frequently bring drugs across the border.

Officials acknowledge a majority of the drugs seized are captured at the legal points of entry. However, numerous border patrol officers and officials told FOX they are struggling to effectively patrol unsecure border crossings while trying to address migrants' processing, medical, and humanitarian needs. Some agents estimate they are spending upwards of 60 percent of their day on humanitarian issues instead of enforcement and drug control.

“They (cartels) are sending people across the border knowing that these fine men and women are going to be tied up with them, and then it's complete carte blanche to send the drugs across,” Carroll said.

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On Tuesday, U.S. customs officials reported a seizure of 191 pounds of meth, concealed within sidewalls of a pickup truck bed at one of the region’s checkpoints. One day prior, officials reported capturing a smuggler with two pounds of cocaine.

FOX’s cameras were permitted wide-ranging access to border facilities but were not allowed to film in areas where migrants are currently being detained. However, border agents stressed the situation remains at crisis levels, with many border facilities packed full of migrants awaiting deportation or a court hearing.

“The people in DC who want to play politics, they should get down here, they should see the president was right, this is a bi-partisan issue, and we’re going to save lives,” said Carroll.

On Tuesday, the Department of Homeland Security reported a 28 percent drop in border apprehensions during June compared to a month prior. DHS officials attributed part of the decrease to more cooperation with the Mexican government.

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However, the number of detained individuals remains a heavy burden on local border patrol officials. Homeland Security continued to describe the situation as a “full blown emergency”.

Vice President Mike Pence and a bipartisan delegation of lawmakers from the Senate Judiciary Committee are scheduled to visit the Rio Grande Valley on Friday. The visit is expected to include a tour of a migrant detention facility and a briefing with border security officials.