A clash on the Libyan border left 14 people dead this week after a convoy loaded with heavy weaponry tried to cross from Libya into neighboring Niger, Reuters news agency reported Wednesday, citing security officials who said the convoy was made up of loyalists of Moammar Gaddafi.

A statement by Niger’s government said that one Nigerien soldier was killed and that 36 assault rifles, 11 machine guns, three rockets and ammunition were seized when troops intercepted the convoy Sunday, according to Reuters.

The incident comes amid growing concern about border security and unsecured weapons in Libya. Under Gaddafi, vast arsenals of munitions including surface-to-air missiles were built up, and the stores were ransacked during eight months of fighting as rebel forces struggled to overthrow the government.

Western military advisers and nongovernmental organizations are working to find and destroy weapons, but security experts say that many have probably been sold to armed North African groups, including al-Qaeda in the Islamic Maghreb.

Coastal Libya and the main population centers are considered relatively secure, but the borders, particularly in the sparsely populated south, remain porous.

The Tuareg nomads who live in the southern desert were Gaddafi loyalists in the early months of fighting this year, and some Libyan officials fear that an insurgency could ignite in the region, with militants slipping easily across borders.

“The Libyan government is obsessed with border security,” said one Western official, speaking on the condition of anonymity. “They worry about Tuareg, mass migration — and they want Saif al-Islam,” he added, referring to the favored son of Gaddafi who is thought to be hiding in border regions.