By Tarek Amara and Erika Solomon
TUNIS | Mon Jul 29, 2013 6:35pm EDT
(Reuters) – Gunmen killed at least eight Tunisian soldiers on Monday, staging the biggest attack on the security forces in decades as political 
tensions rose between supporters and opponents of the Islamist-led government.
President Moncef Marzouki called the ambush on Mount Chaambi, near the Algerian border, a “terrorist attack” and announced three days of mourning. Tunisian troops have been trying to track down Islamist militants in the remote region since December.
Tunisians fear they may be sliding into one of the worst crises in their political transition since autocratic leader Zine al-Abidine Ben Ali was forced to flee during a 2011 uprising that set off revolts across the Arab world.
“We have entered the period of terrorism. We are going to pass through a difficult period but we shall overcome it,” Marzouki said in a televised address. “I call on all politicians at this historic moment to stand for the nation and unite.”
State television cut off normal programming to show pictures of the dead soldiers and wounded comrades, broadcasting Quranic verses and patriotic anthems in the background.
Thousands took to the streets in the town of al-Qasreen, near the site of the attack on the army, many of them demanding the government’s ouster, residents in the area said.
Instability has been rising during the political chaos. Last week, the capital, Tunis, was hit by its first-ever car bomb, though no one was hurt.