Police are investigating a series of bomb threats that were made to York Hospital Saturday evening, police said.

Shortly after 9:30 p.m, York Hospital's call center received multiple phone calls from an anonymous caller stating he planted a bomb on the roof of the hospital, police said.

The hospital's security officers and security systems confirmed there were no unauthorized people on the premises and no bombs were found on the property, police said.

If anyone has any information regarding this incident, they are encouraged to call the York City Police Department at 846-1234.