Bangladesh Telecommu-nication Regula-tory Commission yesterday issued a show cause notice upon Citycell asking the mobile phone operator to explain as to why it was selling unauthorised connections.

The BTRC took the step following threat issued to Prime Minister Sheikh Hasina and her nephew lawmaker Fazle Noor Taposh from Citycell numbers recently.

"We have found at least 26 unauthorised RUIM [removable user identity module] cards," said BTRC Chairman Zia Ahmed, adding that some of the connections have been found to be used in illegal and criminal activities.

Citycell has to respond within 30 days, the chairman said.

He also said the commission will examine the connection selling process of all operators in the country.

Following threats made from Citycell numbers, Rab and BTRC in a joint drive arrested three mobile phone distributors--Lokman Hossain, Rafiqul Islam alias Miraj, Shafiqul Islam alias Ranju--in Dhaka Thursday.