A female suicide bomber has blown herself up in the northwestern Turkish city of Bursa, senior security and government officials said.
Wednesday's blast wounded several people, a security source told the Reuters news agency.
Al Jazeera's Sue Turton, reporting from Istanbul, said officials believed the suicide bomber attacked worshippers gathered at the city's Grand Mosque for prayers.
"The only death we're hearing was herself " Turton said. Officials put the number wounded at 13.
The attack comes shortly after the US embassy issued an emergency warning telling its citizens to avoid tourist attractions due to the threat of attacks.
Turkey has been hit by a number of bomb attacks over the past year as it battles the Islamic State of Iraq and the Levant (ISIL) group, and Kurdish separatist fighters.
Turkish armed forces are involved in military operations against both.
