At least seven people, including one police officer, were injured in an explosion in Istanbul's Beþiktaþ district, broadcaster NTV reported, citing police sources on Thursday.

According to the first reports the explosion occurred beneath a overpass in a garbage can in the city's busy Etiler neighborhood.

Number of injured people is not clear and varies between 7 and 8.

Ambulances, fire engines and police were dispatched to the location of the explosion.

There were no information as to the cause of explosion, although some reports said it could be a small device. The police, fearing a second explosion, evacuated the area.

The explosion took place near Akmerkez, one of Ýstanbul's leading shopping centers, around 9 a.m. Initial reports said one person was injured but Ýstanbul Governor Hüseyin Avni Mutlu and Ýstanbul Police Chief Hüseyin Çapkýn said seven people, including a police officer, were injured in the blast. They said their injuries are not life threatening.

Speaking to reporters at the scene of the explosion, Çapkýn said the explosive was of medium strength, adding it was not a percussion bomb but aimed to create damage. He said five vehicles, including a municipal bus, were damaged in the blast. Çapkýn noted that the bomb had been placed on an electric bike under the bridge.

There are reports that the explosion may have targeted a police academy near Akmerkez.