Tunisian police fired rubber bullets and tear gas at demonstrators in the capital, Tunis, as increasingly violent protests test a government struggling to put its finances in order and attract investors.
Tunisian authorities have arrested 328 people over involvement in "subversive" acts after a third night of protests against price and tax increases, the Interior Ministry said Thursday.
The army has been deployed in Kebeli, Bizerte and the seaside resort city of Sousse among other towns to protect government buildings that have been targeted by protesters.
Peaceful demonstrations erupted last week, but turned violent on Monday and Tuesday as they spread to more than 20 towns including in the suburbs of the capital, Tunis.
Activists campaigning against the austerity measures have called for a huge protest on Friday. The UN said it was concerned about the number of arrests during the protests.
He said Thursday night's protests were "limited", suggesting the situation was calming down. Chahed promised that despite the difficulties in the economic plan, this would be a better year for Tunisians.
At least one person has died and authorities said 330 people were arrested overnight, Reuters reports.
Marches are planned across the country for Sunday to call on the parliament to revise the price rises and mark the so-called Jasmine Revolution, which unleashed uprisings from Egypt to Syria.
Tunisia has been hailed as the only democratic success of the Arab Spring: the one Arab country to topple a long-serving leader in that year's uprisings without triggering widespread violence or civil war.
Protestors have also attacked police stations and government buildings. The 2018 budget also raises customs taxes on some imports, and the government is trying to cut the public sector wage bill through voluntary redundancies.
Unemployment nationally exceeds 15 percent, and is much higher in some marginalised regions of the interior.
Protests have become common in Tunisia in January, the anniversary of the 2011 revolt, which was sparked by the death of Mohamed Bouazizi, a street seller who set himself on fire in a protest over unemployment and police harassment.
The austerity measures are a result of the conditions imposed by the International Monetary Fund and the European Union in return for loans that have gone largely to paying off the country's debts to the international banks.