ISTANBUL

Four people were injured overnight when a homemade explosive went off under an overpass in Istanbul's Maltepe district, on the city's Asian side, security sources said Monday.

Two passengers in a car driving under the overpass and two pedestrians waiting for a taxi were hit by flying pieces of metal and hospitalized, the sources said, speaking on condition of anonymity due to restrictions on speaking with the media.

The blast also damaged some cars passing by.

Police have launched an investigation into the incident.