"On Sunday, armed elements attacked a [military] unit around Natiaboani. The provisional toll is twelve fallen soldiers," a security source told AFP.
Emergency talks in the Ghanaian capital Accra were triggered after Burkina Faso on 24 January became the third member of the 15-nation Economic Community of West African States (Ecowas) to be overtaken by the military.
The coup is the latest bout of turmoil to strike Burkina Faso, a landlocked state that has suffered chronic instability since gaining independence from France in 1960.
West African leaders will meet for a summit on 3 February in Ghana's capital Accra to assess the outcome of the Burkina missions and to decide whether it should impose sanctions as it has done in Mali and Guinea.
Burkina President Roch Marc Christian Kabore was overthrown on Monday by mutineering soldiers on the back of public anger at his failure to stem jihadist violence ravaging the impoverished nation.
Military leaders have detained President Roch Kabore, who reportedly survived an assasination attempt earlier this week.
According to press releases issued by their respective departments, the ministers of foreign affairs, interior, education, and mines and quarries have all tested positive for COVID-19.
The attackers set fire to the church, several shops and a small cafe before heading to the local health centre, which they looted and burnt the chief nurse's vehicle, said Zongo.
On Saturday, the toll stood at four customs officers killed along with the 72-year-old Spanish priest.
