AFP - Iran repelled a cyberattack on Saturday that disrupted the country's internet services for an hour, a telecommunications ministry official said.

"At 11:44 (0814 GMT) a distributed denial-of-service attack disrupted the internet services of some mobile and fixed operators for an hour," tweeted Sajad Bonabi.

A DDoS attack involves overwhelming a target's servers by making a massive number of junk requests.

"Connections have returned to normal following the intervention of Dejfa shield," Bonabi added, referring to Iran's so-called digital fortress against cyberattacks.

He did not elaborate on the source of the attack.

Bonabi is a board member at the ministry's Telecommunications Infrastructure Company, the sole provider of the country's telecommunications infrastructure.

Internet monitor NetBlocks confirmed Saturday's outage and said it was "consistent with a targeted disruption and no technical faults are evident at the present time".

Iran said in December it had thwarted a "highly organised cyberattack" targeting its e-government infrastructure.

Telecommunication Minister Mohammad Javad Azari Jahromi described the attack as "really massive" and "state-sponsored".

In late September, the country's energy sector was put "on full alert" to the threat of "physical and cyber" attacks a few days after Iran denied media reports its oil installations had been disrupted by a cyberattack.

Iranian authorities imposed a near-total internet blackout in mid-November when street violence broke out during demonstrations against a surprise decision to hike petrol prices.

The outage stemmed the flow of videos shared on social media of demonstrations or associated acts of violence.