announcement in an evening TV address to the nation.
Fighting has intensified in recent days in the Swat Valley and other parts of the north-west, and thousands of civilians are leaving the area.
US defence secretary Robert Gates earlier said he was satisfied with Pakistan's anti-Taleban moves.
He said there was "very little chance" of the Taleban achieving the kind of success in Pakistan that they would need to get access to the country's nuclear weapons.
At least 10 soldiers have been killed and nine wounded in the fighting in the past 24 hours, the Pakistani military says.
BBC NEWS | South Asia | Pakistan 'to eliminate militants'