Pakistani officials say a militant commander has blown himself up with a grenade to escape capture during a police raid.
They say four police officers were wounded when the militant, identified as Irfan, committed suicide in Peshawar.
Also Saturday, Pakistani officials said security forces killed two militant commanders during an operation in the Swat region.
Meanwhile, Pakistani Interior Minister Rehman Malik said the army is not needed to secure Karachi.
Local leaders have been increasingly concerned about the spread of violence to Pakistan's commercial center. That concern was heightened after at least eight suspected militants were killed when they accidentally blew up their Karachi safehouse Friday.
Police said at least two suspects were arrested.
Elsewhere Friday, Pakistani officials said at least four people were killed in a suspected U.S. drone (pilotless aircraft) strike in the militant stronghold of North Waziristan.
Officials say missiles hit a house and a vehicle near Miranshah, near Pakistan's border with Afghanistan.
The attack came one day after President Asif Ali Zardari warned that U.S. drone strikes are undermining Pakistan's "national consensus" in his country's war against militants. However, visiting U.S. lawmakers told Pakistani officials the U.S. cannot afford to abandon the controversial missile strikes.