(CNN) -- An explosion rocked a military weapons depot in southern Libya as a group of people apparently tried to loot it, killing at least 20 people, Libya's state news agency LANA reported Friday.
Some people still were missing after Thursday's blast, state-run television reported, suggesting that the casualty figure could rise.
The blast happened at an air force base in Brak al-Shati near the city of Sabha, about 640 kilometers (400 miles) south of the capital, Tripoli.
The base's commander told LANA that the explosion happened after "groups from the area" entered a weapons storage facility to loot ammunition. He said the blast happened because of their lack of expertise in handling the ammunition, without elaborating.
State television, however, quoted one of the injured as saying a group of civilians entered the base in an attempt to steal copper.
More than two years after the fall of Moammar Gadhafi's regime, the government has been struggling to control the country, which is awash in weapons and armed groups. Security officials in southern Libya have voiced concerns about a series of recent incidents of arms looting from military bases.
Other nations have expressed concerns about unsecured stockpiles of weapons in Libya reaching extremist groups in the region.