The Biden administration is crediting strengthened border enforcement and a crackdown by the Mexican government on migrants traveling to the U.S. for a drastic drop in illegal southern border crossings in recent months.

But Republicans argue that the border crisis has not abated. They argue that the administration is playing a shell game, using “unlawful mass-parole programs” to send migrants to ports of entry and letting them into the country “often with little or no vetting.”

According to a report from CBS News, over the first three weeks of May, U.S. Border Patrol agents apprehended about 3,700 migrants per day between official ports of entry, which, if the trend holds, would lead to about 115,000 apprehensions for the month. That would be down from the 129,000 apprehensions in April and 137,000 in May, and a more than 50 percent drop from December when agents made about 250,000 apprehensions.

The Border Patrol apprehensions don’t include the number of migrants processed at official ports of entry.

“We have driven down the number of encounters at our southern border rather dramatically,” Department of Homeland Security Secretary Alejandro Mayorkas told CBS, citing a “number of actions that we have taken, not only strengthening our enforcement, not only attacking the smugglers, but also building lawful pathways that enable people who qualify for relief to reach the United States in a safe, orderly, and legal way.”

But House Republicans contend that despite Mayorkas’s claims, “the border crisis remains at catastrophic levels.” On Wednesday, the House Committee on Homeland Security noted that in April, total Southwest border encounters topped 179,000 and total nationwide encounters exceeded 247,000. Border encounters include both immigrants apprehended crossing the border illegally and those who are processed at official ports of entry.

The committee also noted that the northern border is now experiencing an increase in illegal crossings—a 1,240 percent increase in April compared to April 2021. The Biden administration is on track to hit 10 million encounters at U.S. borders well before the end of the fiscal year, the committee said.

“It is clear that the Biden administration has used unlawful mass-parole programs to shift hundreds of thousands of inadmissible aliens to ports of entry for release into the interior, often with little or no vetting,” the committee said. “The end result is the same—a continuing, historic border crisis.”

Immigration is expected to be a key issue for voters heading into the November presidential election between President Joe Biden and former president Donald Trump, who has vowed to create the “largest deportation effort” in U.S. history if he is re-elected.

Biden, on the other hand, has faced criticism for his handling of the border. It wasn’t until April that Mayorkas conceded before Congress that the surge of illegal immigrants at the southern border does, in fact, constitute a crisis.