Nearly 20,000 fake driver’s licenses and other documents, mainly from China, were seized at Chicago’s O’Hare Airport during the first half of this year.

“Criminal organizations use these false identifications to avoid drawing attention to their illegal activities,” said Ralph Piccirilli, U.S. Customs and Border Protection (CBP) area port acting director in Chicago, according to Fox News Aug. 9.

These false documents encourage crimes such as smuggling, human trafficking, terrorism, and others no less harmful to Americans.

The seizure of false documents are not isolated cases, and they occur at several airports across the country, including New York, Dallas-Fort Worth, Kentucky, and Louisville.

There are concerns about their use in “identity theft, [fraudulent] workplace enforcement, critical infrastructure protection, fraud related to immigration crimes such as smuggling and human trafficking, and false identification of persons associated with terrorism,” said Louisville Port Director Thomas Mahn, according to Fox News.

“What is most disconcerting about these interceptions, in addition to the volume we are experiencing, is the ease with which so many young people freely share their personal information with counterfeiters abroad,” Mann said, according to CBP.

Detecting these fake shipments requires a great deal of dedication from authorities given the resources used by offenders.

For example, a false passport was concealed in the bottom of a package containing only a Chinese tassel, as CBP officials in Memphis discovered and seized nearly 2,000 counterfeit documents.

Although the largest number of licenses comes from China, others also originate from the United Kingdom and South Korea.

“The fraudulent use of identity and travel documents—whether they are false, forged or simply unofficial—is a major threat to both individuals and society as a whole,” warns the International Criminal Police Organization (Interpol).

Interpol issued a special notice to its 194 member countries about the procedures followed by criminals who use websites, vendors, intermediaries, and bank accounts in their crimes, as well as complicated systems to hinder investigations leading to them.

The smuggling of counterfeit documents is particularly dangerous in the run-up to the U.S. presidential election.