Huge explosions rocked a Serbian army ammunition depot early Thursday, injuring at least 10 people, police said.

The explosions at the army barracks near Paracin, about 93 miles south of Belgrade, set off towering fireballs and broke nearly all the windows in the industrial town, state TV footage showed.

The cause of the blasts, which started at around 4 a.m. and lasted for hours, was not known, police said.

Because of the explosions, the authorities sealed off Paracin and closed the main highway leading from the capital, Belgrade, to Serbia's second-largest city, Nis. The highway passes near the barracks.

Police said at least 10 people, mostly from Paracin, were injured by broken glass and flying shrapnel.

Defense Minister Zoran Stankovic said the barracks, which stored large quantities of ammunition and explosives, were evacuated after the first blast, which triggered a tremor felt several miles away.