The signal jamming in the National Assembly ahead of the State of the Nation Address (SONA) last Thursday was caused by an operational error by a member on duty.

This is according to State Security Minister David Mahlobo, who said the operator failed to properly terminate the device and this impacted on proper access to some users of mobile phones.

“A departmental investigation is currently underway with a possibility of disciplinary action for those responsible for this operational failure,” the department said in a statement on Wednesday.

On Thursday, journalists and some MPs protested against cellphone signals being blocked in Parliament.

Journalists protested in the press gallery because they could not file their stories – chanting "Bring back the signal, bring back the signal”.

The signal was restored after National Assembly Speaker Baleka Mbete asked the secretary to Parliament to look into the matter.

In the statement, Minister Mahlobo confirmed that the State Security Agency was responsible for threat and risk assessment and that on the day the agency was supporting SA National Defence Force efforts to enforce airspace security.

The SONA event was rated major based on intelligence reported prior to the event which was unprecedented.

Furthermore, given the magnitude of the event and the fact that all spheres of government, the three arms of the State, international invited guests, two former Heads of State and the general public were present, maximum security had to be effected, explained Mahlabo.

As part of the security measures, it meant that there was a no fly zone over Parliament and the areas surrounding it.

“The deployment of these counter intelligence measures where the Heads of State and Government attends is in line with international risks assessment and crisis management procedures.”

Regretting what he called the “unintentional disruption” – the Minister said that there was no executive or political decision to interfere with the free flow of information.

The department, according to the minister, will in future ensure that its members in discharging their operational tasks handle their operations more diligently.

“This operation was never intended to frustrate the Parliamentarians, the media and anyone who attended Parliament and the result of it not being switched off properly is highly regretted,” Mahlabo assured.