(CNN) -- Eight soldiers were killed in an ambush near the Algerian border, Tunisia's president said Monday.
The attack took place on Mount Chaambi, some 300 kilometers south of Tunis, the capital, President Moncef Marzouki said in a statement posted to his Facebook page.
Later, a security patrol was struck by a landmine in the same area. Three soldiers were injured in that attack.
Marzouki blamed Islamic militants and extremists for the violence.
He announced three days of mourning for the victims.
Last week, a Tunisian opposition leader was fatally shot outside his home, setting off protests in a nation still raw from the February assassination of a different politician who opposed the Islamist-led governing party.
The slaying of Mohammed Al-Brahmi and the public's reaction were the latest bout of turmoil striking the North African country that had been seen as a poster child of stability after the 2011 Arab Spring uprisings.