One man has been killed and 16 injured by a bomb at an internet cafe in Istanbul's Bayrampasa district, Turkish authorities have said.
The internet cafe was used by police officers from a nearby base
The cafe was often used by police from a nearby headquarters. Seven officers and a child were among the wounded.
A Kurdish militant group - the Kurdistan Freedom Falcons (TAK) - claimed responsibility for the blast.
Militant Islamists carried out a series of bombings in Istanbul in November 2003 which killed more than 60 people.
People near the internet cafe said the blast had been very powerful.
"I head a loud explosion and felt the ground move. It was like an earthquake. I ran to the shop and there was blood on the ground," said machine worker Murat Seymen.
He had helped carry injured people out of the building, he told Reuters news agency.
Medical officials said a 21-year-old man had died from his wounds after being taken to hospital.
A 13-year-old boy was reported to be among those hurt.
The pro-Kurdish Firat News Agency, based in the Netherlands, said TAK had phoned to say it had carried out the bombing.
TAK is believed to be linked to the main Kurdish rebel group, the Kurdistan Workers Party (PKK).
The group wants jailed PKK leader Abdullah Ocalan to be moved out of solitary confinement, the Associated Press reports.
TAK was blamed for a series of bomb attacks in Turkey last year, including one in the holiday resort of Kusadasi in July which killed five people, including two foreign tourists.
The PKK has been blacklisted as a terrorist organisation by Turkey, the US and the European Union. It has been fighting the Turkish authorities since 1984 in a drive for self-rule in the country's mainly Kurdish south east.