UPDATE: Police determined the threat was not credible. New details HERE.

An investigation is underway after someone made a bomb threat against three Philadelphia police districts, according to officials.

Officials say a person alerted a 39th District officer about a message on Facebook which stated someone would blow up three Philly police districts with a bomb.

“We received information that there have been threats made against several of our patrol districts,” a Philadelphia Police spokesman told NBC10. “Obviously, we are taking this seriously and it will be thoroughly investigated in order to ensure the safety of not only our employees, but the residents who live in the aforementioned districts.”

The threat comes less than a week after a gunman shot and killed five police officers during a protest in Dallas. Police departments across the country have been on high alert since the incident, which was the deadliest attack on police officers since September 11, 2001.