A bomb ripped through a bus in southern Afghanistan on Friday killing 14 civilians as the Taliban, accusing NATO forces of genocide, threatened to step up already rising suicide attacks. “We want to inform the foreign forces and their slaves that their defeat is inevitable in Afghanistan,” Taliban commander Mulla Dadullah told Reuters by satellite phone from a secret location. “The Taliban are ready to fight until death and in the coming days will increase their activities and suicide attacks to such an extent that the infidel forces will not get a chance to rest,” he said.The warning came as a provincial official said a bomb had killed at least 14 civilians in Uruzgan province. The blast tore through a bus, but officials said it was not clear if it was a suicide attack or a roadside bomb. Dadullah denied NATO charges the guerrillas used villagers as human shields in combat against foreign forces. NATO chief Jaap de Hoop Scheffer blamed the Taliban for NATO killings of Afghan civilians, saying the Islamist militia was taking “human shields” to try to ward off attacks, the White House said.