Customs officials in Philadelphia recently seized more than $6.5 million in fake U.S. currency from Russia.

The counterfeit bills were discovered last Tuesday after arriving in five parcels air-mailed to an address outside Chicago, according to a statement from the U.S. Customs and Border Protection.

The Secret Service later confirmed the cash was phony.

Authorities have not indicated any suspects who might be responsible for the shipment.

“This is an outstanding interception by Customs and Border Protection officers of an alarming amount of restricted currency that may be altered to look authentic and potentially used to hurt our nation's most vulnerable citizens."

- Edward Moriarty, CBP’s acting area port director in Philadelphia

A manifest identified the fake loot as “Play Money for Monopoly,” although the bills looked like real cash, Customs officials said.

In a separate case, Customs agents seized nearly $100,000 in counterfeit euros and American dollars in early September.

But the latest shipment was much larger, with more than $3 million worth of euros in denominations of 10, 50, 100 and 500.

Previously, authorities confiscated $20,500 in fake $1 bills in one parcel on Sept. 14. Another $2 million in fake $100 bills was seized on Sept. 16 along with $15,000 in fake $1 bills in separate parcels; $990,000 in fake $100 bills were discovered on Sept. 17.

“This is an outstanding interception by Customs and Border Protection officers of an alarming amount of restricted currency that may be altered to look authentic and potentially used to hurt our nation’s most vulnerable citizens,” said Edward Moriarty, CBP’s acting area port director in Philadelphia. “CBP remains committed to working with our law enforcement partners in our collective efforts to interrupt financial scams and to protect our nation’s economic security.”

On Sept. 28, U.S. Customs officers found $228,000 in genuine cash inside two commercial vehicles crossing the Canadian border at the Ambassador Bridge in Detroit, according to the Windsor Star. The money was seized, and the drivers were released.