An explosion in the Turkish city of Istanbul near the country's ruling party's headquarters has injured at least 16 people, most of them policemen, the Turkish state news agency reports.
Istanbul police chief Huseyin Capkin said an explosive device was placed on a motorcycle and set off by remote control as a police vehicle drove past, near the Justice and Development Party (AKP) building and the offices of a conservative business association.
"As a police vehicle carrying 21 officers was passing by, a remote control bomb on a motorcycle exploded. Our teams are carrying out the investigation," Capkin told reporters, adding that none of the injured were in critical condition. Fifteen of the injured were police officers, the Anatolia news agency reported.
Huseyin Avni Mutlu, the governor of Istanbul, said the device was composed of plastic explosives.
State media reported that a vehicle and a police bus were damaged in the explosion early on Thursday morning in the Sutluce district.
The bus came to a halt about 50 metres away, said an eyewitness. Forensic teams quickly covered it in blue nylon sheets as experts searched the cordoned-off area for fragments of the bomb.
Police had immediately sealed off the area, as a precautionary measure were a second explosion to occur. There was no initial claim of responsibility.
Istanbul has been a target of periodic bombings in recent years, including a 2008 bombing blamed on Kurdish separatist fighters that killed 17 people and injured scores more.
Three people were killed in Ankara, the Turkish capital, in September last year in a bombing claimed by a group called the Kurdistan Freedom Hawks (TAK), which Turkish officials say is a front used by the Kurdistan Workers Party, or PKK.
"We will never bow to such attacks," Recep Tayyip Erdogan, the Turkish prime minister, told a televised news conference after Thursday's attack. "We will continue our struggle against terrorism and the culprits will be captured as soon as possible."