Dozens of Islamist fighters have stormed through the Tunisian town of Ben Guerdan near the Libyan border attacking army and police posts in a raid that killed at least 53 people, including civilians, the government and residents say.

Local television broadcasted images of soldiers and police crouched in doorways and on rooftops as gunshots echoed in the centre of the town.

Bodies of dead militants lay in the streets near the military barracks after the army regained control.

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Authorities sealed off the nearby beach resort town of Djerba, a popular destination for foreign and local tourists, imposed a curfew on Ben Guerdan and closed two border crossings with Libya after the attack.

“I saw a lot of militants at dawn, they were running with their Kalashnikovs,” one resident, Hussein, said.

“They said they were Islamic State (IS) and they came to target the army and the police.”

It was not clear if the attackers crossed over the border, but it was the type of militant operation Tunisia’s government had feared as it prepares for potential spill-over from Libya, where IS militants have gained ground.

Since its 2011 revolt to oust ruler Zine El-Abidine Ben Ali, Tunisia has struggled with Islamist militancy at home and over the border.

Militants trained in jihadist camps in Libya carried out two attacks last year in Tunisia.

“This was an unprecedented, well-organised attack,” President Beji Caid Essebsi said.

“But the people in the south can be confident the army and police will win against this barbarity across the border.”

Soldiers killed 35 militants and arrested six, the Interior Ministry said.

Hospital and security sources said at least seven civilians were killed along with 11 soldiers.

Troops also later discovered a large cache of rifles, explosives and rocket-propelled grenades in Ben Guerdan, a security source said.

“If the army had not been ready, the terrorists would have been able to raise their flag over Ben Guerdan and gotten a symbolic victory,” said Abd Elhamid Jelassi, vice president of the Islamist party Ennahda, part of the government coalition.

Islamist militant gunmen trained in Libyan jihadist camps carried out two of the three major attacks on Tunisia last year, including assaults on the Tunis Bardo museum and a Sousse beach hotel targeting foreign tourists.

– with agencies