Announcing the deployment, President Beji Caid Essebsi said the troops would protect industrial sites being disrupted by general strikes and protests over poverty.
"We know this is a serious decision but it must be taken," Essebsi said in a speech in Tunis on Wednesday. "Our democratic path has become threatened and law must be applied but we will respect freedoms."
The 2011 protests, which brought an end to the 23-year-rule of former President Zine El Abedine Ben Ali, were largely driven by the lack of economic opportunities for young people.
Key economic sectors include textiles and apparel, food products, petroleum products, chemicals and phosphates, with 60 percent of exports going to France, Italy and Germany.
Essebsi singled out the phosphate industry in the central mining region of Gafsa that had "come to a halt for five years."
"What do we have? We have phosphate, petrol and tourism, we have agriculture," Essebsi said. "The state must also protect the resources of the Tunisian people."
Tourism accounts for about 8 percent of the Tunisian economy and was badly hit by two attacks on foreigners in 2015, but officials said they expected the sector to recover this year, with bookings up on 2016.
Protests around oil and gas operations
The southern Tataouine province where Italy's ENI and Austrian firm OMV have gas operations have been the focus of protests and a group of demonstrators camped out in the desert, threatening to blockade roads as they demanded more jobs and access to the region's natural riches. OMV said last week it had moved some 700 non-essential staff and contractors from its operations as a precaution.
Protests have also broken out in nearby Kebili province and on Wednesday police fired tear gas to break up protests in a town west of Tunis after a fruit seller set himself on fire in protest against the police.
Many of those who feel excluded from Tunisia's mainstream have set up civil society organizations or developed informal networks, without any intention of joining the formal political sector.
"When they (demonstrators) get angry, they cut off roads. The roads belong to everyone and the state must face this," the president said on Wednesday. "I warn you from now," dealing with the military will become "difficult," he said.
Tunisia's energy minister, Hela Chikhrouhou, said on Monday that since 2010 oil production had fallen to 44,000 barrels per day, with revenues slumping by a third to about $400 million (368 million euros).
Young, educated and heading out
With unemployment at more than 15 percent, economic benefits from the political changes which ended autocratic government six years ago have largely failed to materialise. A third of unemployed people have a college degree.
Today, Tunisian youth make up 60 percent of the population. A recent survey by international, academic research group Arab Barometer found that more than half of Tunisians aged 18 to 24 wanted to emigrate from their country, compared to just 13 percent of those aged 35 and above. While the "architecture of political democracy" has been successfully installed, the Barometer reported, "the substantive benefit of democracy - the translation of citizens' needs and priorities into concrete policy solutions - has in many ways remained elusive."
A nationwide state of emergency has been in effect in Tunisia since November 2015 following a suicide attack that killed 12 presidential guards.
jm/kms (dpa, Reuters)