PESHAWAR  - A nine-year-old girl was killed and three other children were wounded Monday when a bomb exploded near their school gate in a tribal region in northwestern Pakistan, officials said. The bombing took place outside a village school in the tense North Waziristan region where the Pakistani military has been battling Taliban militants since June 2014.

"A nine-year-old girl was killed and three other children between eight to 10 years old were wounded when explosives planted close to their school gate exploded when they opened it," a local government official told AFP.

A local security official also confirmed the blast. The tribal areas are off-limits to journalists and it is impossible to independently verify incidents. The army launched an operation in June 2014 in North Waziristan to wipe out militant bases in the region and bring an end to a bloody insurgency that has cost thousands of lives since 2004. As a result security has improved. Scattered attacks still take place, but fewer than previously.