Militants blew up part of a newly constructed government school in South Waziristan late Friday night, a spokesperson for a wing of the Tehreek-e-Taliban Pakistan (TTP) said on Saturday, the latest in a string of attacks on educational institutions.No one was hurt in the blast in Pakistan's restive tribal belt, but 18 labourers working on the site were abducted, said Azam Tariq, a spokesperson for an arm of the TTP known as the "Sajna" group, which claimed responsibility for the attack.He said the workers were released a short time later."We have blown up the school because it was a government installation," said Tariq, warning the group would continue to attack government targets.Twenty people were killed and dozens wounded last month when militants launched an attack on Bacha Khan University in K-P, a little more than a year after Taliban gunmen massacred 134 students at the Army Public School in Peshawar.The Peshawar school attack was seen as having hardened Pakistan's resolve to fight militants along its border with Afghanistan.Officials in South Waziristan said the girls' wing of the school in the Tehsil Tiarza area was damaged in Friday's blast, as well as some heavy machinery being used for ongoing construction at the site.In a separate incident in Mohmand tribal area to the north, security officials killed five militants during a clash near Mohmand Agency's administrative headquarters on Saturday.The militants were planning an attack in the area, a security official said, speaking on condition of anonymity.A generation of Pakistani militants have used the tribal region to launch attacks on the Pakistani state and US-led forces in Afghanistan.The Pakistani Taliban are fighting to topple the government and install a strict interpretation of Islamic law.They are loosely allied with the Afghan Taliban who ruled most of Afghanistan until they were overthrown by US-backed military action in 2001.