By Tarek Amara
TUNIS (Reuters) - Tunisia's prime minister said on Saturday that the country's young democracy would be preserved "whatever the cost" following four days of violent job protests and riots, and that it would take time to respond to young people's economic demands.
An interior ministry spokesman said the situation was calm across most of the country, a day after authorities imposed a nationwide nighttime curfew.
The demonstrations that began in the impoverished town of Kasserine on Tuesday and spread across the country are the most serious since the 2011 uprising that toppled autocrat Zine El Abidine Ben Ali.
Tunisia has been held up as a model for democratic progress since the 2011 revolution. But there has been rising discontent over a lack of jobs and high living costs, especially in the country's interior.
The country is also facing a threat from Islamist militants, who launched three major attacks last year and have been gaining strength in neighboring Libya.
Prime Minister Habib Essid told a news conference that he understood the demands of young Tunisians, but said people seeking to "destroy the democratic transition" had taken advantage of the protests.
"I appeal for calm and for national unity and complete security across the country to preserve our nascent democracy which is the only example of success in the region," he said.
"There has been huge political progress but we acknowledge that there are lots of economic difficulties. We will respond to young people's economic demands but we need a bit of time for that."
He said Tunisian democracy would not be destroyed, "whatever the cost".
The curfew began on Friday, when there was further violence in the capital, Tunis. The interior ministry said almost 70 people had been arrested for damaging property or theft.
Protests this week have seen demonstrators storm police stations and local government buildings and clash with riot police. One policeman has been killed and dozens injured.
"Tunisia's stability and security has been targeted," President Beji Caid Essebsi said in a televised address late on Friday. "Even Daesh (Islamic State) in Libya wants to take advantage of this situation of violence."
(Writing by Aidan Lewis; Editing by Digby Lidstone)