A large number of police officers went to the scene along with bomb disposal units after the blast, which took place near an electrical transformer on Millet Street in İstanbul's Fatih district, Today's Zaman reported.
Preliminary examinations revealed that the explosion stemmed from a hand-made cluster bomb. No one was injured in the incident, according to news agencies.
Meanwhile, in Maltepe, a suspicious package was discovered in front of an Ataturk statue in the courtyard of a municipal police station.
The package -- which bore a note reading "Cizre will be avenged" -- turned out to be a cluster bomb and was detonated by bomb disposal experts.
The pieces of the bomb were taken to a police station for examination.
The note likely referred to the killing of a 12-year-old by police during demonstrations in Cizre, a town in southeast Turkey.
In Sultangazi, another İstanbul neighborhood, a group of people wearing masks left a suspicious package at a bus stop on Adem Yavuz Street.
Upon calls from passersby, police in armored vehicles arrived at the scene and blocked two lanes of traffic.
A bomb disposal team arrived and detonated the bomb.
The initials of the Patriotic Revolutionary Youth Movement (YDG-H), the youth branch of the outlawed Kurdistan Workers' Party (PKK), were written on the package.