Beirut , Lebanon ( CNN ) -- An unintentional fireworks explosion rocked downtown Beirut on Thursday , injuring five civilians who were working with a local non-governmental organization , a Lebanese interior security forces source told CNN . The blast , which occurred around 8 p.m. ( 1 p.m . ET ) , left a crater on fire next to Martyr 's Square . Those hurt were working with the fireworks for a celebration on Thursday , which is Army Day in Lebanon , when a large firework never launched and instead exploded on the ground , the security forces source said . They 'd been working on a grassy area , which is one reason that there was no significant damage to nearby buildings , despite the substantial size of the blast . Ambulance crews and firefighters converges on the scene , the latter trying to put out flames that had spread into the grass . Watch : Fireworks disasters .
An accidental fireworks explosion rocks downtown Beirut . 5 who 'd been working with the fireworks are hurt , a security forces source says . Score: 6