Istanbul, April 10 (IANS): Three people were injured when an explosion hit an overpass of a metro bus stop in Istanbul's Mecidiyekoy neighbourhood on Saturday night.

The blast was caused by a nylon bag left on the overpass, the Haberturk daily said. The Cumhuriyet daily said the cause was a stun grenade.

Police evacuated shopping malls nearby over the possibility of a second explosion, with special teams securing the area, Xinhua quoted the Haberturk as saying.

The police have launched a large-scale investigation, joined by anti-terror and crime scene investigation teams, the reports said.

The explosion came as Istanbul has been on edge over more possible terror attacks, since the metropolis and Ankara, the national capital, have come under six deadly attacks over the past eight months, with the last one hitting Istanbul on March 19 and killing four foreign tourists.

Israel and the US have issued alerts over the past two days about the risk of fresh terror attacks in Turkey, with the US Embassy in Ankara warning of threats to tourist sites in Istanbul and Antalya, a coastal city in the southwest.

Police in Istanbul have been on high alert following the US warning on Saturday, Turkish media said, as the city is scheduled to host the 13th summit of the Organisation of Islamic Cooperation later this week.