"Around 9 a.m., during a mass, armed individuals burst into the Catholic Church. They started firing as the churchgoers tried to flee," Dablo Mayor Ousmane Zongo told AFP.
A security source told the agency that the attack was carried out by a "group of armed men estimated [to number] between twenty and thirty."
In late April, several armed people attacked a Protestant church in Silgdji in the north of the country, killing five churchgoers and the pastor. The April attack was the first attack on a church since 2015.
The attacks comes as the authorities of Burkina Faso have launched a massive anti-terrorist operation in the eastern and central-eastern regions of the country.