By Tarek Amara and Erika Solomon
TUNIS (Reuters) - The suspension of Tunisia's transitional parliament could bring the birthplace of the Arab Spring uprisings closer to an "Egyptian scenario" in which the secular opposition topples an Islamist-led government, analysts and politicians say.
The biggest shock to the ruling Ennahda party, the Tunisian branch of the Muslim Brotherhood, may be that the latest blow came from one of its own secular allies - a sign of rising polarisation between Islamist and secular forces.
"This is a win for the opposition. It moved the crisis inside the coalition government," said analyst Nourdine Mbarki.
Constituent Assembly President Mustafa Ben Jaafar, a member of junior coalition partner Ettakatol, froze the legislature's work on Tuesday until talks are started between the government and the opposition.
Ben Jaafar said he took the step to "guarantee the transition to democracy." But fellow assembly member and Ennahda leader Najib Mrad called it an "internal coup".
Tunisia is facing the most severe political and security crisis since a 2011 uprising toppled autocratic leader Zine el-Abidine Ben Ali and sparked a wave of "Arab Spring" revolts across the Middle East.
The secular opposition, angered by two assassinations in its ranks and emboldened by Egypt's army-backed ouster of an Islamist president, has held daily mass protests in a bid to topple the government and dissolve the Assembly.
The move comes just weeks before the transitional body is due to finish a draft constitution and electoral law that would allow Tunisia to hold fresh elections by the end of the year.
"The Egypt scenario is not far off and seems quite possible if the crisis continues," said Tunisian political analyst Sofian Ben Farhat, though he said Tunisia's army was unlikely to help.
Historically it has not intervened in politics, as Egypt's army has on several occasions. The Egyptian military deposed and detained freely elected president Mohammed Mursi on July 3 after mass anti-Muslim Brotherhood protests. Security forces launched a crackdown and arrested several Brotherhood leaders.
International diplomatic efforts to resolve the standoff in Cairo collapsed on Wednesday, raising the prospect of bloodshed if the government dislodges pro-Mursi protest sit-ins by force.
RESHUFFLING THE CARDS
In contrast with Mursi's decisions to ram through an Islamist-tinged constitution and reject power-sharing with the secular opposition, Ennahda has governed in coalition with secular partners and refrained from introducing Islamic law into the constitution.
"Freezing the assembly along with mass protests could reshuffle the political playing cards and lead us into a new and more dangerous turn in the crisis if the opposition and the government continue their stubbornness," Ben Farhat said.
Ennahda has said it is willing to hold talks but refuses to dissolve the Assembly or remove the prime minister. Major opposition leaders boycotted talks last weekend and say they will not back down from their demands.
Opposition figures say their pressure tactics are working.
"The mass mobilisation and Ben Jaafar's decision will quickly bring us to what happened in Egypt," said Sofian Chouarbi, an opposition activist who rose to prominence in the 2011 revolt that sent former President Zin al-Abidine Ben Ali fleeing into exile in Saudi Arabia.
"The opposition stepped up its pressure and Ben Jaafar responded."
Tunisia was once held up as a model for transition among fledgling Arab democracies. Now, it faces worsening divisions at the same time that it faces a growing security crisis - Islamist militants have been stepped up attacks across the country.
Tunisians are struggling with the same issues that countries like Egypt face - how to respect the results of free elections and respond to popular discontent and impatience with economic stagnation, high unemployment and a steep fall in tourism.
Adding to tensions is the bitter competition between secular opposition groups and the Islamist parties that rose to power in popular elections.
Though Ennahda denies any interest in imposing Islamic law, the opposition is wary. It also says Ennahda has been soft on Islamist militants suspected of assassinating the two leftist opposition figures.
ENNAHDA PLAYS DOWN RISKS
Ennahda leaders are playing down the seriousness of the parliament suspension and say instead it will help them get the opposition to reach a compromise through talks.
"This decision hasn't weakened Ennahda but rather will force the opposition to start talks," said Ennahda politician Lotfi Zeitoun. "I expect dialogue will start soon after the Eid holiday (on August 8) and the Assembly won't stay frozen long."
That may be wishful thinking - if anything, the opposition appears to think the suspension justifies its hardline stance.
"You saw the people in the streets. Dissolving the Assembly is the people's demand," said Beji Caid Sebsi, head of Nida Touns, an opposition party with ties to the ousted Ben Ali.
"Ennahda's proposal for a referendum isn't serious talk, its just an effort to buy time but conditions will force the dissolution of the government too," he said.
On Monday, Ennahda leader Rachid Ghannouchi challenged the opposition to a referendum to decide whether or not to remove the government and the assembly.
He urged patience in the face of what he called a counter revolution, arguing new elections were only months away.
"The street cannot change an elected government, only a dictatorial one," he said. "We accept correcting the transition path, but we won't accept an absurd and nihilistic one."
Ennahda is still a force to be reckoned with. Last weekend, more than 100,000 crowded into a main square of Tunis to support the government, in the biggest rally since Ben Ali's ouster.
But the party is running out of influential partners. The powerful Tunisian General Labour Union has thrown its weight behind the Assembly suspension and backed opposition protests.
The 600,000 strong union could be a decisive player in determining the outcome of the crisis, given its ability to paralyse much of the country if it called a strike.
In a sign of the potential for more violence, activists of the "Committee to Protect the Revolution" have clashed with anti-government protesters in the past few weeks.
Amid the political chaos, ordinary Tunisians are watching with dismay what many see as an ugly power struggle.
"The opposition wants to ride the wave of recent regional events but it isn't offering us anything other than more protests," says 25-year-old Nadia Youssfi, standing outside a grocery store in downtown Tunis.
"Why can't we all just wait a few months and have elections? Ennahda is bad. But now the opposition is worse. They're using our youth as fuel to obliterate the government and parliament and take us into a void," she said.
(Editing by Paul Taylor)