The telecom regulator today directed all the mobile phone operators to complete biometric re-registration of their roaming clients immediately.

Bangladesh Telecommunication Regulatory Commission (BTRC) issued a letter today and directed operators to block all roaming SIMs if their customers fail to biometrically re-register their connection within seven days.

This particular group of subscribers will be given seven days time from the date of their arrival to complete verification by showing their passport and arrival details, said a senior official of the telecom regulator.

Mobile operators said they have received the letter and will comply with it.

"All the roaming numbers are postpaid and most of those are verified with authentic information," Md Sarwar Alam, spokesperson for BTRC, told reporters.

However, they need to re-register the SIM immediately after coming back to home, he added.

Mobile operators started re-registration process on December 16 last year and it ended on May 31.