Sources said that three militants identified as Ahmed Jameel Mughal alias Fahadullah Fahad, Saqib alias Haji Yaqoob and Farhan were arrested in a joint operation by police and intelligence agencies.
The arrested suspects are allegedly involved in attacks on security and NATO forces in Pakistan and Afghanistan. They were also said to be behind the terrorist incidents and attacks on police officers in Karachi.
Nine mm pistols, hand grenades and explosives were recovered from the arrested suspects.
The arrested men have been transferred to undisclosed location for interrogation, sources said.