Two Spanish journalists abducted near a nature reserve in eastern Burkina Faso have been killed, Prime Minister Pedro Sánchez said.
Local security sources say an Irish national was also killed, though this has not been officially confirmed.
The Europeans were part of an anti-poaching patrol that was ambushed by gunmen near Pama Reserve on Monday. A local soldier was also abducted.
No group said it had carried out the attack.
Burkina Faso is facing a deepening security crisis, like many of its neighbours, as Islamist armed groups carry out raids and kidnappings across much of the region.
What do we know about the attack?
The patrol on Monday included soldiers, forest rangers and foreign reporters.
Two soldiers wounded in the ambush told the Associated Press news agency the attack had been launched by jihadists who had outnumbered the 15-person patrol.
One of the soldiers was shot in the leg and the other in his arm, causing it to be amputated, AP reports.
Vehicles and weapons were seized in the attack.
Spanish Foreign Minister Arancha González Laya told reporters that bodies found in the area appeared to be those of two Spanish journalists who had been filming a documentary.
Mr Sánchez later tweeted: “The worst news is confirmed.”
He named the journalists as David Beriain and Roberto Fraile, and praised “those who, like them, carry out courageous and essential journalism from conflict zones”.
Local officials told media outlets that an Irish national on the patrol had also been killed.
In a statement to the BBC, Ireland’s department of foreign affairs said: “The Department is aware of the reports and is liaising closely with international partners regarding the situation on the ground.”
A senior security source told AFP news agency that the three Europeans had been “executed by terrorists”.
Details of what happened to the local soldier who was abducted were not immediately clear.
What’s the background?
The kidnappings are the latest in the former French colony where wildlife reserves used to be popular with tourists.
But many of them are in territory now targeted by jihadists.
Militant Islamist groups are believed to be holding several foreigners hostage in Burkina Faso, as well as in the neighbouring states of Mali and Niger, Reuters news agency reports.
The semi-arid region, known as the Sahel, has been hit by an insurgency since the militants captured large parts of northern Mali in 2012 and 2013.
France and other foreign allies have deployed troops to the region but have failed to end the insurgency.
The conflict has displaced nearly three million people.