An army spokesman, Major General Nasser Janjua, made the comments Saturday at a news conference in Mingora, the main town in the region. He said the army has arrested 143 militants since it began an operation last month to recapture the valley from supporters of a radical pro-Taliban cleric.
He said five soldiers and six civilians also were killed in the operation.
But he said militant leader Maulana Fazlullah fled to nearby mountains with at least 200 militant supporters. The army spokesman said some 20,000 troops will continue operations to target the militants there.
The army said last month that it shut down the FM radio station that Fazlullah used to call for strict Islamic law and a holy war against the government.
Hundreds of troops have been fighting Fazlullah's pro-Taliban insurgents who have seized control of a series of small towns and villages in Swat, Pakistan's top tourist destination in North West Frontier Province.
The rebel advance in Swat marked a move out of the country's tribal regions near the border with Afghanistan.
Some information for this report was provided by AFP.