Pakistan on Monday announced a plan to hang around 500 convicted terrorists as police arrested suspects believed to have abetted Taliban gunmen who killed 135 children at a school last week.
The executions were expected to take place in three weeks' time, said Musadik Malik, spokesman for Prime Minister Nawaz Sharif.
"There will be no mercy for those who have killed our children, citizens and soldiers," the spokesman quoted Sharif as saying in the capital Islamabad.
Sharif's government lifted a six-year moratorium on executions after Taliban gunmen stormed an army-run school in the north-western city of Peshawar last Tuesday, killing 148 people including 135 students.
All the assailants were killed by army commandos.
Six militants convicted of attacks on the army headquarters and former military ruler Pervez Musharraf have since been hanged in the central province of Punjab, according to provincial Home Minister Shuja Khanzada.
Interior Minister Chaudhry Nisar Ali Khan said on Sunday police had arrested suspects behind the attack - the deadliest ever in Pakistan - warning that militants might be planning more "savage" activities.
"A few suspects who were facilitators in one way or another have been taken into custody," Khan told media in Islamabad.
The minister did not disclose the identity of those arrested or confirm their exact number, saying only that they were being interrogated by police and other security agencies.
Another Interior Ministry official told dpa the arrests were made in and around Peshawar and that six suspects including a woman were picked up from a remote town in the central province of Punjab.
Taliban spokesman Muhammad Khorassani said the attack was to avenge a military offensive launched in June to regain control of the country's tribal regions from Islamist militants linked to Al-Qaida.
Police commandoes killed at least two militants believed to be behind the attack in clashes in Peshawar city and its suburbs on Saturday, a military statement said.
The Taliban on Saturday threatened to carry out jailbreaks if the government did not stop the executions of their fighters.
Authorities deployed troops to guard prisons where detained militants were being kept and tightened security at airports, railways stations and in all major cities.
All schools, colleges and universities were closed for winter vacation one week earlier than scheduled.
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