Photographs from the scene showed the severed torso of what appeared to be the bomber lying at the side of the mosque.
There was no immediate claim of responsibility.
“The attack was carried out by a suicide bomber. It is a woman, and she is dead. According to the information we have at the moment, seven people are wounded,” the government official told Reuters.
Turkey has been hit by a series of suicide bombings this year, including two in its largest city Istanbul blamed on Islamic State, and two in the capital Ankara which were claimed by a Kurdish militant group. It has also faced attacks from far leftist groups, mostly on police and security forces.
Bursa is Turkey’s fourth largest city, an industrial hub directly south of Istanbul across the Marmara Sea and a city rich in Ottoman-era architecture.