Witnesses say about a dozen people were wounded and some reports state two of three suspected gunmen have been arrested.
Video posted to social media showed a large number of emergency vehicles outside the mosque, with the area cordoned off by police.
Five people are believed to have been shot dead in a Quebec City mosque, according to the mosque's director.
Gunfire was reported at the Islamic Center of Quebec at around 8 p.m.
Yangui, who was not inside the mosque when the shooting occurred, said he got frantic calls from people at evening prayers.
In June a year ago, during the month of Ramadan, a pig's head was left on the doorstep of the mosque. Eating pork is prohibited in the Islamic faith.
This story is developing and will be updated.