Islamabad, Jan 30 (IANS): Over two million mobile SIM cards have been blocked across Pakistan, a media report said Friday.

The cards have been blocked under a campaign launched by the government for verification of mobile phone subscribers' details , Dawn online reported.

Earlier this month, the government gave Pakistan Telecommunication Authority (PTA) 91 days to verify 103 million SIM cards issued before August 2013 but not verified through the Biometric Verification System (BVS).

Since the exercise began Jan 12 this year, PTA has re-verified 8.72 million subscribers.

The three-month period to verify mobile phone connections through the BVS expires April 13.

"Three months is not realistic time for such an uphill task but such are the directions from the interior ministry," PTA chairman Syed Ismail Shah said.

According to earlier schedule, the process of verification was to be completed in a year.

"But it is now necessary after the terror attack at a school in Peshawar Dec 16, 2014," Shah said.

SIMs not verified within the 91 days, would be blocked, the PTA chairman said.

The PTA chairman defended the mobile companies and said that they would suffer significant losses by blocking unverified SIMs and they had spent money on installing the verification system.

Under a system introduced Jan 2009, subscribers had to respond to two 'confidential' questions - mother's name and place of birth - for activation of SIM cards.

The system worked fine till January 2013, when voters' list was made public for that year's elections.

The list included answers to the confidential questions and resulted in SIM activation.