Pakistan hanged four people on Sunday in the second set of executions since the government lifted a moratorium on the death penalty after the Taliban massacred 132 children and nine others at a school last week.
None of those hanged has anything to do with Tuesday's school rampage in Peshawar, and some Pakistani commentators have said the executions are intended to divert attention from the failure to satisfy public demands to find the killers.
Four prisoners were executed at the tightly guarded Faisalabad jail for their role in attacking former Pakistani president Pervez Musharraf, a senior government official told Reuters. Two others had been hanged at the same jail on Friday.
A source in the local Punjab government identified the four as Rasheed Qureshi, Zubair Ahmad, Ghulam Sarwar and Akhlaque Ahmed, also known as Russi, who he said was Russian.
Authorities told The Associated Press that several other arrests were made Sunday in connection with the school attack case.
"Quite a few suspects who were facilitators in one way or the other have been taken into custody," Interior Minister Chaudhry Nisar Ali Khan told the AP, adding that the interrogations were "moving ahead in a positive manner." He did not disclose their identities or say how many they were.
Pakistan is home to a range of militant groups, many of them linked to Al-Qaeda, based in lawless tribal areas. They include an unknown number of foreign fighters, thought to be mostly Arabs, Uzbeks, Chechens and Uighurs.
Official sources said more convicts would be executed in coming days, some of them in the city of Lahore, the power base of Prime Minister Nawaz Sharif.
The Taliban have issued statements promising to stage more attacks around Pakistan in retaliation for the executions of any of their fighters.
Security has been tightened around major prisons, reflecting fears that the Taliban fighters, who are fighting to topple the government and set up a state governed by Islamic law, might try to attack jails and free inmates.
Rights groups believe Pakistan has about 8,000 prisoners on death row, more than 500 of them for alleged terrorist offenses.
The U.N. human rights office appealed to Pakistan on Friday to refrain from resuming executions.
Phelim Kine, deputy Asia director at the U.S.-based Human Rights Watch, said on Sunday the government had "chosen to indulge in vengeful blood-lust instead of finding and prosecuting those responsible."