A Tunisian soldier holds his position during an exercise along the frontier with Libya in Sabkeht Alyun, Tunisia, Feb. 6, 2016. Tunisia has completed a 200-km (125-mile) barrier along its frontier with Libya to try to keep out Islamic militants. REUTERS/Zoubeir Souissi

BEIRUT — Clashes between militants and Tunisian security forces erupted Monday on Tunisia's border with Libya. At least 28 militants, seven civilians and 10 security forces were killed in the operation, according to a statement from Tunisia’s Ministry of Interior.

Tunisian security officials have sealed off two border crossings with Libya and blocked entry to Djerba , a nearby beach town popular with locals and foreign tourists. Tunisian security forces were still searching the area for additional militants, according to the local state news agency TAP.

Dozens of fighters were involved in the cross-border attack — the second since last week — on army positions and local hospitals in the vicinity of the Ras Ajdir border crossing and the nearby town of Ben Guerdan.

Militants reportedly targeted a National Guard army barracks and a government building, but clashes reached civilian areas. Hospital official Abdelkrim Chafroud told Agence France-Presse a 12-year-old patient was among those killed in the clashes. Early reports said militants had stolen two ambulances, but International Business Times was not able to independently confirm the claim.

"I saw a lot of militants at dawn, they were running with their Kalashnikovs," Hussein, a resident of Ben Guerdan, told Reuters. "They said they were Islamic State [group fighters] and they came to target the army and the police."

Tunisia has become increasingly vulnerable to the threat posed by the group, also known as ISIS. Despite the North African country's reputation as the only success story of the 2011 Arab Spring uprisings, it has not escaped the spreading threat of jihadists. A December report from the intelligence and risk consultancy Soufan Group revealed that of the 81 countries that have citizens fighting in Syria, Tunisian nationals make up half of the estimated 12,000 foreign fighters.

The threat is not only from within: Many ISIS fighters have crossed into Tunisia from Libya, where a chaotic civil war has left a power vacuum that has given way to the rise of terrorist organizations vying for power. In response to the growing threat, the Tunisian government completed construction of a roughly 125-mile barrier that runs along its border with Libya last month to minimize the risk of cross-border raids and terrorist infiltration.