Philadelphia police said Thursday night that they are investigating the theft of COVID-19 vaccination cards and N95 masks from a Penn Medicine clinic in Center City.

The confirmation of the investigation came after KYW News Radio reported that 5,000 cards had been taken from Pennsylvania Hospital, which is run by Penn Medicine.

Police, in a summary of the theft report, said the actual number of cards stolen was unknown.

A spokesperson for Penn Medicine said in a statement: “Safety and security are top priorities in all of our facilities. When this issue was discovered, we promptly reported it to the Philadelphia police and are cooperating fully with the ongoing investigation.”

The spokesperson did not know how many cards were stolen.

Police said that on Jan. 25 a senior director for the Pennsylvania Hospital vaccine clinic called police to report a theft of vaccine cards and N95 masks from a storage room used by the clinic at 245 S. Eighth St.

Police said all hospital staff members have access to the storage room and there was no sign of forced entry.