Sixteen Iranian nationals illegally in the United States were arrested by President Donald Trump’s administration over the past few days. The arrests come as the president has criticized former President Joe Biden for allowing Iranian “sleeper cells” to illegally enter the country.

In a Tuesday press release, the Department of Homeland Security announced that U.S. Immigration and Customs Enforcement (ICE) arrested 11 Iranian nationals over the weekend who were illegally in the United States. The press release also noted that ICE officials arrested a U.S. citizen who “threatened to kill ICE law enforcement while harboring an illegal alien from Iran.”

The Department of Homeland Security emphasized that the arrest of Iranian nationals illegally in the United States reflects the agency’s dedication to “keeping known and suspected terrorists out of American communities.”

“Under Secretary Noem, DHS has been full throttle on identifying and arresting known or suspected terrorists and violent extremists that illegally entered this country, came in through Biden’s fraudulent parole programs or otherwise,” Assistant Secretary of Homeland Security Tricia McLaughlin said. “We have been saying we are getting the worst of the worst out—and we are. We don’t wait until a military operation to execute; we proactively deliver on President Trump’s mandate to secure the homeland.”

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According to Fox News, in addition to the 11 Iranian nationals arrested by ICE over the weekend, at least five other Iranian nationals were arrested by law enforcement officials on Monday. The outlet noted that the 16 arrests come as officials have expressed concerns regarding potential actions by Iranian “sleeper cells” in the United States in light of the Trump administration’s military strikes against Iran’s nuclear program over the weekend.

During a press gaggle while traveling on Air Force One on Tuesday, Trump was asked about the potential for Iranian “sleeper cells” in the United States. In response, the president said, “Biden led a lot of sleeper cells in. Biden was an incompetent president. He had no idea what he was doing. Hardly ever signed a document. Other people signed documents for him with the auto pen.”

“It was gross incompetence,” Trump added. “And among everything else, he let a lot of sleeper cells in, many from Iran, but hopefully we’ll take care of them. What Biden did to this country should never be forgotten.”