State-owned carrier Teletalk's failure to kill around 22 lakh unregistered connections is allowing a huge volume of illegal international calls to be made, depriving the government of revenue.

Mobile service providers have started the process to block more than two and half crore active mobile subscriptions as of zero hour today, for the users' failure to complete biometric re-registration as per government decree.

Subscribers using biometrically unregistered SIM cards will have their outgoing calls blocked after today, while incoming calls are likely to stay active for “a few hours”, according to a top official of a telecom operator.

Time for biometric SIM re-registration, which was scheduled to end today, has been extended to May 31, says State Minister for Posts and Telecommunications Tarana Halim.

Telecom operators had to deal with a last-minute rush of mobile phone users yesterday, with the deadline for biometric SIM re-registration expiring today.