RAWALPINDI, Jan 11: Security officials have been barred from using cellular phones while performing duties during President Pervez Musharraf's movements, sources revealed.

Besides, a strict observation of the personnel associated with the president's security has been ordered. Wireless messaging during the president's movement has also been restricted.

The precision with which the two assassination attempts on the president's life were carried out sparked concern among the security planners, who feared that the terrorists could have infiltrated the security ranks.

Special emphasis was laid on this aspect during the subsequent investigations into the two incidents. The investigators were able to trace one possible link, which to some extent showed that the vital information about president's movement had been provided by a Special Branch sleuth, who had been part of Gen Musharraf's security on December 25, 2003.

The low level Special Branch employee, who has been identified as Mohammad Naeem, was later picked up for investigations and is still being interrogated.

It is being suspected that he had informed the suicide attackers about the departure timings of president's motorcade from Convention Centre.

Information in this regard came from the examination of calls records of one of the suicide bombers, whose cellular phone's SIM was recovered from the site of the blast.

Naeem apparently did not have any connection with religious groups, his colleagues said. Besides, Naeem several other Special Branch employees have been interrogated regarding the incident.

One other aspect being actively probed is that why had some of the senior officials overlooked an alert regarding the December 25 incident.

Meanwhile, it has been learnt that the authorities have decided to revamp the route security of the president. Regarding the modifications, the source said, the roads will be closed for two-way traffic during the president's movement. Barriers would be set up on all link roads to the main highways used for the president's movements. Similarly, barriers would also be erected on U-turns falling on link roads and main highways.