ISTANBUL: An explosion caused by a homemade bomb rocked an Istanbul metro station on Tuesday, triggering panic in the evening rush hour and wounding up to half a dozen people. The local mayor and the state-run Anatolia news agency confirmed a bomb caused the blast, which came at a time of growing jitters over security in Istanbul and the risk of a militant attack in Turkey’s largest city. The blast, which was heard in several areas of the city, hit an overpass close to the metro station in the Bayrampasa district of Istanbul. The metro system in Istanbul was brought entirely to a halt after the blast, the municipality said, although normal service was gradually restored. Anatolia said it was being investigated whether the bomb had been aimed at a police bus that was damaged in the attack.