LONGMONT, Colo. -- Severe weather emergency sirens malfunctioned early Thursday morning, waking up residents in Longmont.
The sirens started blaring about 4 a.m. across the city and lasted until after 5 a.m., startling several residents who were sleeping.
The city of Longmont said the sirens set off a tone that is not normal for the Outdoor Emergency Warning System.
"This system is designed to be remotely turned off. However, due to the malfunction, the system required manual shut off at all 17 posts located throughout the city," the city said in a statement.
The Longmont Police Department said it received numerous calls about the sirens. It stressed there was no emergency in the city and it was working to shut off the sirens.
The cause for the malfunction was not known and the system has been turned off for officials to troubleshoot it.