UPDATE: After an investigation by police, ATF and firefighters, no explosive devices were found at Plaza Tower in Tyler. Evacuated employees were allowed back into the building.

Here is the original story:

A bomb threat in downtown Tyler has caused an evacuation of the Plaza Tower. Although the evacuations were not called for by the fire department, occupants have voluntarily gathered on the square.

Many federal and financial offices are located in the Plaza Tower which is notable as the tallest building with 21 floors. According to KLTV.com, fire crews and police responded at 10:44 a.m.

An employee on the 10th floor of the building reportedly received a phone call that multiple explosive devices were placed throughout the building. Officials from Tyler Police and Fire Departments and the ATF are on the scene investigating.

Building employees were waiting outside on the square.