Calgary police are investigating a bomb threat at a downtown law firm.

CPS Acting Detective, Jody Cross says a call came into Medicine Hat Police around 8:45 p.m. on Wednesday evening. The caller told the Medicing Hat police to tell Calgary police that a bomb was planted at a business in the 300 block of 7 Avenue SW.

The caller reportedly said the bomb was set to go off Thursday.

Police say they are searching the 10th floor of First Canadian Centre and the Tact Team has been called in.

LRT service has not been disrupted.