An explosion at Brussels’ Maalbeek subway station has left at least 15 people dead Tuesday, shortly after a blast hit the city’s airport. The city’s transportation authority has shut down all Metro stations in the city. Pierre Meys, a spokesman for the Brussels fire brigade, confirmed the death toll. Maalbeek is near the European Union’s headquarters. Authorities are asking people in the area to use online messaging apps to communicate with friends and family because cellphone networks are being overwhelmed.