Dallas police are responding to a "possible active shooter" at an office building in the Texan city.
Police have provided no other details, including whether any shots have been fired or any injuries were reported in emergency calls.
KOB4: RT Maria_NBC5: Dallas police in SWAT gear, armored vehicles surround office building at Schroeder and 635 af… pic.twitter.com/E59F3mvbh4
— Georg Thomas (@SupportWFam) April 24, 2017
Television footage shows a heavy police response at a multi-storey office building along an interstate in northern Dallas.
People can be seen milling around outside the building.
Police moving us back from this area. Officer says as far as they know this is still active shooter situation. Unknown if broken glass assoc pic.twitter.com/qNtDegBtND
— Maria Guerrero (@Maria_NBC5) April 24, 2017