TUNIS 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.
After clashes between pro- and anti-government protesters on Monday, the army sealed off the main Bardo square in the capital with barbed wire and declared it a "closed military zone." Demonstrators on both sides vowed to return in the evening.
The secular Ettakatol party, a junior coalition partner, called on the moderate Islamist Ennahda party, which leads the government, to step down, saying a new administration representing a wider consensus was necessary. "If Ennahda rejects this proposal, we will withdraw from the government," Lobni Jribi, a party leader, told Reuters.
Prime Minister Ali Larayedh ignored the calls to create a new unity government and said he would carry on leading the country.
Protests aimed at ousting the government intensified last week after the second assassination of a politician from the secular opposition in six months. The government blamed hardline Salafist militants for both attacks, but the opposition holds Ennahda responsible, arguing that its leadership has not done enough to investigate and crack down on militant attacks.
PRESSURE MOUNTS TO DISSOLVE GOVERNMENT
Despite previous unrest, Tunisia had been a model for democratic transition among the "Arab Spring" states. But divisions are growing between the opposition - emboldened by the Egyptian army's ousting of elected Islamist President Mohamed Mursi - and Ennahda supporters, who are determined to avoid a similar fate.
"In all countries of the world, when the state faces a terrorist attack the people come together. But I don't see anything like that happening now in Tunisia," Marzouki said. "All we see is divisions and chaos."
The opposition may be able to mobilize Tunisians further against the government after Monday's ambush, which shocked the country and increased anti-government sentiment on social media.
This week the opposition rejected all concessions and efforts at reconciliation by Ennahda, arguing that its leaders bumbled for too long and that their time was up. It is planning to create its own rival "salvation government."
Tunisia's powerful General Union of Tunisian Workers was in talks with the opposition on Monday, and has said it may discuss a strike. Last Friday, its strike called to mourn the assassinated leftist politician, Mohamed Brahmi, paralyzed much of the country.
Larayedh struck a note of defiance in a speech on Monday, calling the opposition protesters "coupists." He also challenged his critics to act constructively.
"We are open to all kinds of dialogue with all sides. We want specific proposals," he said. "Any precise suggestions regarding increasing the effectiveness of the government, bring them forward."
A Constituent Assembly is only weeks away from completing a long-delayed draft constitution to be put to a referendum.
The secular opposition has called for the 217-member Assembly to be dissolved. In the last few days, 70 lawmakers have left the body and set up a sit-in protest outside its headquarters.
In the city of Sidi Bouzid, angry protesters tried to storm municipal offices to stop employees from going to work, residents said, provoking clashes with Ennahda supporters.
The army intervened to protect the offices and police fired teargas, but residents said thousands of demonstrators were gathering in the southern city, the cradle of Tunisia's revolt.
Many people joining the growing street protests have expressed anger at Tunisia's instability and economic stagnation.
Others are frustrated that the constitution, originally promised one year after the 2011 uprising, has yet to be completed and are suspicious of the transitional government.
(Reporting by Tarek Amara and Erika Solomon; Additional reporting by Brian Love in Paris; Writing by Erika Solomon; Editing by David Stamp and Eric Beech)