Ten police officers were killed and three wounded in an ambush in northwestern Burkina Faso on Thursday, the west African country's security ministry said.
"The toll is 10 officers who have lost their lives and three wounded," the ministry said in a statement, adding that a police convoy from the Toeni region and reinforcements from the Dedougou area had been ambushed.
The officers were attacked while heading to the village of Loroni, near the border with Mali, after a school there had been attacked and textbooks torched by armed assailants, a security source told AFP.
The wounded, including two in serious condition, were taken to a hospital in Dedougou, the source added.
Burkina Faso has been increasingly hit by deadly attacks over the last three years.
They began in the north of the country but have since spread to the east, near the border with Togo and Benin.
On Wednesday, a police officer died during an attack on his station in the northern town of Solan.
Most attacks are attributed to the jihadist group Ansarul Islam, which emerged near the Mali border in December 2016, and to the JNIM (the Group to Support Islam and Muslims), which has sworn allegiance to Al-Qaeda in the Islamic Maghreb.
Those groups are believed to be responsible for more than 255 deaths since 2015.
The capital Ouagadougou has been hit three times and almost 60 people have died there.