MAIDUGURI, Nigeria: A purported spokesman for Nigeria's Boko Haram Islamists late Monday threatened the group would soon launch attacks on mobile telephone firms for their alleged complicity with security agents.

In a phone conference with reporters in the northeastern city of Maiduguri, a man who claimed to be Boko Haram spokesman Abul Qaqa said the sect would "soon launch attacks" on mobile phone operators and state-run regulator Nigerian Communications Commission (NCC).

He accused them of complicity with security agents in bugging the phones of sect members to track them.

"We have realised that the mobile phone operators and the NCC have been assisting security agencies in tracking and arresting our members by bugging their lines and and enabling the security agents to locate the position of our members," he said.

Boko Haram has previously used similar conferences with journalists in Maiduguri, capital of Borno state, the group's base, to make public statements.

"It was with the connivance with the mobile phone companies operating in Nigeria and the NCC that the security agents were able to locate Abu Dardaa and Kabiru Sokoto and arrest them," Qaqa said in the local Hausa language.

Nigeria has five major mobile phone operators with a total subscriber base of around 90 million.

South Africa-based MTN is the largest mobile operator in Nigeria. Other operators include the United Arab Emirates' Etisalat and Indian-owned Airtel.

Early this month, security sources said they had arrested Abul Qaqa, but the Islamists rejected that claim, saying another senior Boko Haram member, Abu Dardaa, was the one in custody.

On Friday, Nigerian security agents re-arrested Kabiru Sokoto, a prominent sect member in a village in eastern Taraba state, four weeks after his escape from police custody in suspicious circumstances.

Sokoto is believed to be the mastermind of the Christmas day bombing of a church near Nigeria's capital Abuja that killed at least 44 people.

Boko Haram's deadliest attack yet occurred on January 20, when coordinated bombings and shootings killed at least 185 people in Nigeria's second-largest city of Kano.

The group also claimed responsibility for the August suicide bombing of UN headquarters in Abuja that left at least 25 people dead.

It has in the past claimed to be fighting for an Islamic state in Nigeria's mainly Muslim north, but its demands have repeatedly shifted.