Updated

An official says the air traffic control tower at Baltimore-Washington International Thurgood Marshall Airport was evacuated briefly after the fire alarm went off.

Airport spokesman Jonathan Dean said in an email that the airport's fire department responded to a report of a fire alarm at the tower about 6:45 a.m. Tuesday and investigated. He says firefighters didn't find smoke or fire.

Dean says tower functions were suspended briefly, but personnel returned to work about 15 minutes later.

Dean didn't know how many flights were delayed, but he says the overall effect was minor. He says the cause of the alarm is being investigated.