Security forces on Sunday killed eight militants in Swat valley, where the army is battling extremists waging a violent campaign for Islamic law, officials said. Troops launched a pre-dawn operation against a militant hideout in the town of Ningolai, a military spokesman said. "The clash left eight militants dead including their commander Nur Bakhtiar," said the spokesman, who requested anonymity. Heavy arms and ammunition were recovered from the hideout, he added. Pakistan's military is battling extremists loyal to radical cleric Maulana Fazlullah who have launched a violent campaign to introduce Islamic Sharia law. Swat, once a popular destination for Pakistani and foreign holidaymakers, has descended into chaos in recent months, with pitched battles between militants and security forces.