Kabul, Afghanistan (CNN) -- Ten girls were killed in eastern Afghanistan on Monday when a landmine exploded as they were out collecting firewood -- the latest casualties in one of the most mined countries in the world. Two other girls were injured in the incident in Nangarhar province, said Ahmad Zia Abdulzai, the spokesman for the province's governor. Landmines -- those planted by insurgents and those left over from the Soviet occupation -- continue to kill dozens of Afghans every year. "Naturally curious, children are likely to pick up strange objects, such as the infamous toy-like 'butterfly' mines that Soviet forces spread by the millions in Afghanistan," according to UNICEF. Read more: The low-tech, high-design tumbleweed minesweeper designed by former Afghan refugee .
Two others are injured in the blast . Landmines continue to kill dozens in Afghanistan .