Federal officials said Wednesday they have seized some 11 million fake N95 masks, including 1 million earlier today, as part of a federal investigation into the foreign-made knockoffs that have been distributed to hospitals, medical facilities, and beyond in at least five states.

The fake masks closely resemble N95 masks produced by Minnesota-based company 3M. The counterfeit products have been sold to states "from coast to coast" with officials expected to seize more phony N95s in the "coming weeks," Alejandro Mayorkas, the U.S. Secretary of Homeland Security, said during a briefing Wednesday.

This December 2020 image provided by U.S. Immigration and Customs Enforcement (ICE) shows a counterfeit N95 surgical mask that was seized by ICE and U.S. Customs and Border Protection. Federal investigators are probing a massive counterfeit N95 mask operation sold in at least five states to hospitals, medical facilities, and government agencies and expect the number to rise significantly in coming weeks. The fake 3M masks are at best a copyright violations and at worst unsafe fakes that put unknowing health care workers at grave risk for coronavirus. And they are becoming increasingly difficult to spot. (ICE via AP)

The sellers of these counterfeit masks "take advantage of our fears to make a quick buck," he added, noting that federal officials are "working closely with 3M to identify ‘bad actors,’" in a scheme they said has been ongoing since April, shortly after the pandemic began.

At this time, no criminal charges have been made, but are expected, they said.

Officials did not identify either the states or companies under investigation, but Washington state officials found that 300,000 masks purchased for about $1.4 million were counterfeit, a spokesperson for 3M recently confirmed to Fox News. Overall, 3M has filed more than a dozen lawsuits over reports of fraud and counterfeiting as demand for the small, tight-fitting masks skyrocketed across 2020. N95s are considered the gold standard in protection against the novel coronavirus.

Investigators also notified about 6,000 potential victims in at least 12 states including hospitals, medical facilities and others who may have unknowingly purchased knockoffs, urging them to stop using the medical-grade masks. Officials encouraged medical workers and companies to go to 3Ms website for tips on how to spot fakes.

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The phony masks are not tested to see whether they meet strict N95 standards and could put frontline medical workers at risk if they are used while treating patients with COVID-19.

Nearly a year into the pandemic, fraud has remained a major problem overall, with federal officials saying during the briefing that they have also seen an increase in phony websites purporting to sell vaccines as well as fake medicine produced overseas and scams involving personal protective equipment.

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So far during the pandemic, Homeland Security Investigations has used its 7,000 agents, along with border officials, the Food and Drug Administration and the FBI, to investigate the scams, seizing $33 million in phony products and arresting more than 200 people. The effort is based at the National Intellectual Property Rights Coordination Center, a government watchdog aimed at enforcing international trade laws and combating intellectual property theft.

3M, based in Maplewood, Minnesota, is among the largest global producers of the N95 mask, which has been approved by the U.S. National Institute for Occupational Safety and Health. The company delivered some 2 billion N95 masks in 2020 as the pandemic intensified, but in the earlier months, when masks were in short supply, fraudsters took advantage.

Fox News' Peter Aitken and the Associated Press contributed to this report.