Newly-confirmed Attorney General Bill Barr laid out in stark terms the negative effects of a porous border, in a Monday speech before the National Association of Attorneys General.

Barr preceded his warning by noting the rising number of opioid deaths in the United States, particularly the effects of Chinese fentanyl, which is used by Mexican drug cartels to augment the effects of their heroin supply. “The DEA has stated publicly that the Mexican trans national criminal organizations are the greatest criminal drug threat to the United States,” Barr declared, adding “the DEA tells us that the majority of the heroin, cocaine, methamphetamine and fentanyl in this country got here across our southern border.”

“Having a porous southern border makes every state more vulnerable to these drugs,” Barr continued, saying that “the problem with the porous border is not limited to drugs,” and that “it creates opportunities for human trafficking, one of the most heinous criminal acts there is.”

Barr’s comments come amid a high-profile fight between President Donald Trump and Congress about the current situation at the U.S. southern border. The United States detained approximately 70,000 migrants at the southern border in February, a dramatic spike from the previous month.

Trump declared a national emergency at the border in February, which authorizes him to appropriate approximately $3.6 billion to begin construction of his proposed wall.

The national emergency was quickly challenged by Congress, where the House of Representatives last week passed a disapproval resolution. The resolution must now be taken up by the Senate, where four Republican senators have stated that they will join their Democratic colleagues in voting for the resolution. (RELATED: 3 Senate Republicans Are Banding Together To Support Resolution To Terminate Trump’s National Emergency)

The senators each say they oppose the move because they believe it to be an unconstitutional action by Trump to circumvent the congressional appropriations process. Trump, however, has vowed to veto any disapproval legislation which would effectively end the process as the Congress does not have the necessary two-thirds majority to override the president’s action.