TORONTO -- Countries should be on the lookout for counterfeit COVID-19 vaccines, as they are an easy target for crime networks, according to Interpol.

After sending out a global alert about the potential for fake doses, 2,400 doses of fake vaccines were seized in South Africa, the agency said in a statement. They also recovered counterfeit 3M masks and arrested four people.

In China, 80 suspects were arrested and 3,000 doses of fake COVID-19 vaccines were seized. Interpol believes this is just a fraction of a much larger issue.

“Whilst we welcome this result, this is only the tip of the iceberg when it comes to COVID-19 vaccine related crime,” Interpol Secretary General Jürgen Stock said in a statement.

The arrests and seizures followed an alert sent out by the agency warning law enforcement agencies of the high potential for crime networks to target COVID-19 vaccines. The alert also provided details on how authentic COVID-19 vaccines are shipped and what they look like, according to the statement.

The investigations into fake COVID-19 vaccines are ongoing and Interpol has received information that networks selling fake vaccines are targeting not just countries, but health groups like long-term care homes, the statement said.

In the early months of the COVID-19 pandemic, Canada was plagued by counterfeit N95 masks. More recently, Procurement Minister Anita Anand alerted the public and the RCMP of nefarious groups offering vaccine doses to Canada.

Interpol put out a warning to the general public that vaccines are not being sold online.

“Any vaccine being advertised on websites or the dark web, will not be legitimate, will not have been tested and may be dangerous,” a statement read. “Anyone who buys these drugs is putting themselves at risk and giving their money to organized criminals.”