Iranian authorities cut off internet services to several politically sensitive parts of the country ahead of calls for renewed protests against the regime on Thursday.

An unnamed source cited by the semi-official Iranian Labour News Agency said mobile internet service had been shutdown on Wednesday in Alborz province adjacent to the capital Tehran, the central province of Fars which includes the city of Shiraz, as well as the ethnically volatile provinces of Kordestan to the west and Zanjan to the east.

The shutdown was confirmed on social media by Iranians who raised fears the move was intended to shut the country off from the world ahead of a violent crackdown like those last month that left hundreds dead.

NetBlocks, an internet mapping organisation, described “disruptions to mobile networks” in multiple Iranian cities, “although the extent of the disruptions has not yet been corroborated.”

The unnamed source cited by ILNA said the shutdown was “based on an order by security bodies,” a likely reference to the Supreme National Security Council, which includes Supreme Leader Ali Khamenei, President Hassan Rouhani, the head of the Revolutionary Guards and other key security and political figures.

It suggests the authorities remained fearful of the possibility of more popular rebellion as the country fends off a United States campaign of sanctions meant to destabilise the country over its pursuit of nuclear technology, refinement of missiles and its support for armed groups throughout the Middle East.

Video posted on social media suggested bolstered deployments of police and extremist Basiji militiamen throughout parts of the capital.

The hardline Fars news agency has published videos showing prisoners in striped uniforms "confessing" to killing security forces while they were peacefully at prayer in the southwestern city of Mahshahr last month, a tactic meant to intimidate potential opponents by showing the extent of the regime's coercive power.

Tensions high as Trump approves new Iran sanctions: In pictures Show all 17 1 /17 Tensions high as Trump approves new Iran sanctions: In pictures Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, their surface-to-air missile is seen as it shoots down a US surveillance drone EPA Tensions high as Trump approves new Iran sanctions: In pictures This photo shows US RQ-4A Global Hawk unmanned surveillance drone. A drone of this model was shot down by Iran on Thursday 21 June AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures An oil tanker is on fire after it was subject to a suspected attacked at the Gulf of Oman on June 13. The US has blamed Iran for the attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures US President Trump holds up a signed executive order to increase sanctions on Iran on 24 June AP Tensions high as Trump approves new Iran sanctions: In pictures Iranian President Rouhani stated in a televised address that the White House is "afflicted by mental retardation" following the increase in sanctions on 25 June EPA Tensions high as Trump approves new Iran sanctions: In pictures An Iranian navy boat tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Iran claims that in this picture released by Iran state TV, debris from the downed US drone is seen after it was recovered from Iranian waters AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures A screenshot from a video released by the US Department of Defense that the US claims to show Iranian removing an unexploded limpet mine form the hull of the Japan-owned ship that was attacked in the Gulf of Oman on June 13 Getty Tensions high as Trump approves new Iran sanctions: In pictures An item reportedly found on the Japan-owned oil tanker that was attacked on June 13 in the Gulf of Oman AFP/Getty Tensions high as Trump approves new Iran sanctions: In pictures A handout photograph from the US Department of Defense shows a composite material that the US claim was left behind on the hull of the Japan-owned oil tanker following the removal of an unexploded limpet mine Getty Tensions high as Trump approves new Iran sanctions: In pictures A view from the cabin of an Iranian navy boat as it tackles the fire on the Norwegian owned Front Altair oil tanker after it was hit in a suspected attack EPA Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The picture suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack Reuters Tensions high as Trump approves new Iran sanctions: In pictures Smoke billows from an oil tanker after it was subject to a suspected attacked at the Gulf of Oman on June 13 Reuters Tensions high as Trump approves new Iran sanctions: In pictures Release by US government A picture released by U.S. Central Command shows damage to the hull of the oil tanker Kokuka Courageous. The pictures suggests that the ship is 'likely' to have been hit by a mine as the US Secretary of State Mike Pompeo moves to blame Iran for the suspected attack EPA

Iran was roiled by days of protests last month sparked by a sudden spike in fuel prices that exacerbated public anger over economic troubles and political repression.

Unnamed sources cited by Reuters claimed 1,500 people were killed in the November protests and the State Department has claimed up to 1,000 dead in the unrest. Iran has dismissed the figures as exaggerated but has yet to cite an official death toll.

Regime officials shut down the internet for six days after the protests, badly damaging the country’s nascent tech sector while cutting the country off from the world.

Three out of four Iranians use mobile internet.

The demonstrations called for Thursday are meant to commemorate those killed last month. They were first called by the father of Pooya Bakhtiari, a 27-year-old protester shot dead by regime agents on 16 November. Thursday marks the 40th day since his death, a religiously significant mourning milestone in the Islamic faith.