Authorities in a number of U.S. cities are responding to bomb threats that were received via email Thursday, according to published reports.

Cities where the threats have been received include Atlanta; Boston; Chicago; Columbus, Ohio; Dallas; Detroit; Oklahoma City; Orlando;  South Bend, Ind.; and Tampa. 

Oklahoma City police told The Oklahoman that multiple bomb threats were made toward a number of sites across the metro, including Wiley Post Airport.

Capt. Bo Mathews said 10 to 13 threats have been made via email for locations in Oklahoma City.

Although none of the threats appear credible, Mathews said officers are treating the threats as though they are real.

In Ohio, the Columbus Dispatch reported that an administrative building at Capital University was evacuated. Multiple businesses throughout Franklin County also received threats.

Columbus police asked businesses that receive threats to check their location for anything suspicious or out of place. If nothing is out of place, the businesses were being asked to call and make a report with police.

If something is out of place, police asked the businesses to call back and officers will respond like a bomb threat.

The threats continue to be investigated by Columbus police, state and federal authorities to try and determine where they originated. 

And in Texas, police in Round Rock, just north of Austin, reported eight bomb threats had been received citywide, according to the Austin American-Statesman.

Investigators believe the threats are not credible, Round Rock police spokesman Nick Olivier said, and are working to confirm their origination.

“They believe at least two of (the threats) originated overseas,” he said.