Pakistani troops have killed between 50-60 Islamist militants during fierce fighting in the restive northwestern Swat valley, the army says. "The reports which I have from the police and Frontier Corps people who were doing this law enforcement action was about 50-60 militants died yesterday," Army spokesman Major-General Waheed Arshad said.Swat, a scenic valley close to Pakistan's lawless tribal belt bordering Afghanistan, has seen a surge in militant activity since Maulana Fazlullah, a pro-Taliban cleric, reportedly launched an illegal FM radio station and urged a jihad, or Muslim holy war.