NEW YORK — The Senate's top Democrat says federal law enforcement officials need to crack down on fake COVID-19 vaccination cards being sold online.

Sen. Chuck Schumer's announcement Sunday comes after The Associated Press reported how people are cheating the system and buying counterfeit COVID-19 vaccination cards online, worrying officials at colleges and universities across the country that are requiring proof students received the vaccine to attend in-person classes.

Schumer is demanding U.S. Customs and Border Protection and the FBI team up with officials from the Department of Health and Human Services to launch a crackdown on the counterfeit cards and start a campaign to make clear that forging the cards could land people in federal prison.

He also wants the Justice Department to immediately prioritize cases involving fake vaccine cards and is pushing for Customs and Border Protection to work harder to find counterfeit cards being sent from overseas.

Federal agents have already seized thousands of fake vaccine cards this year. Customs and Border Protection officers working in Memphis seized another shipment earlier this week — sent from Shenzhen, China and headed to New Orleans — that contained dozens of fake cards, officials said.

The FBI had issued a joint statement with the Department of Health and Human Services in March urging people not to buy, create or sell fabricated vaccine cards. The unauthorized use of the seal of an official government agency is a federal crime that carries a possible fine and a up to five years in prison.