According to the police, the accused are involved in the kidnapping of slain Punjab province Governor Salman Taseer's son Shahbaz Taseer and an American national, Warren Weinstein.
The militants - identified as Usman Basra, Naimutallah Uzbak, Mufti Mohsin alias Jalaluddin, Farhaj Mustafa, Rana Abdur Rehman and Muhammad - have been arrested from different parts of the Punjab province, police said.
During interrogation, the accused confessed to committing kidnappings of Shahbaz and Warren and killing Shia cleric Irfan Naqvi. Both Shahbaz and Warren are still in captivity and believed to be held in areas bordering Afghanistan.
Police said the arrest might lead to the safe recovery of Taseer junior and the American national.