A female suicide bomber has blown herself up in a historic district of Turkey's fourth largest city, wounding 13 people.

The assailant was "aged about 25", and only fragments were left of her body after the attack in the city of Bursa, according to Turkey's health minister, Mehmet Muezzinoglu.

He said 13 individuals were injured in the attack, but none of them are in critical condition. Another seven people sought medical attention over ear pain and hearing problems as a consequence of the blast.

Turkey, which is facing growing difficulties stemming from the conflict in Syria and renewed conflict with Kurdish militants, has recently witnessed a surge of such attacks. In the past year, more than 200 people across the country have been killed in seven suicide bombings.

Bursa governor Munir Karaloglu said authorities are still trying to determine the identity and affiliation of the attacker.

He denied reports that two other accomplices were seen fleeing the scene, saying they were citizens fleeing in panic and that the woman acted alone.

The explosion ripped through an area that is home to an Ottoman-era mosque and bazaar in the north-western city, which is a popular tourist destination for both locals and foreigners.

Turkish TV channels broadcast footage of people fleeing the area as police and ambulances rushed to the scene.

The attack occurred a day after the United States issued a new warning to its citizens about "credible indications" of terrorist threats against tourist areas in Turkey.

Kurdish militants, who have been fighting state security forces in a renewed conflict in the south-east, have claimed two such attacks recently.

But the main perpetrator, according to Turkish authorities, has been Islamic State (IS), which controls territory in neighbouring Syria and Iraq.

The extremist group is known to have cells in Turkey but never claimed responsibility for any of the suicide attacks on Turkish soil.

Speaking in Ankara before travelling to Qatar, Turkish prime minister Ahmet Davutoglu stressed "these terror attacks will not cause Turkey to step of back from its resolute stance to fight terrorism".

Turkey is a member of the US-led coalition against IS, allowing allied jets to carry out bombing runs against the militants from its bases.

Turkish tanks periodically fire at IS targets in Syria in response to cross-border missiles which have claimed 18 lives in the border town of Kilis this year.