An enormous explosion at a port in Iran has killed at least 14 people, with at least 750 people reportedly injured.

Massive plumes of smoke billowed from Shahid Rajee, a complex within a port in Bandar Abbas in Iran’s southwest.

Terrifying vision of the disaster quickly spread on social media, showing the thick, dark smoke rises from the blast.

Know the news with the 7NEWS app: Download today

Hours after the blast, the fire had spread, with fears the entire port could burn to the ground.

Efforts were ongoing to extinguish a significant fire, with the port’s customs saying that trucks were being evacuated from the area and that the container yard where the explosion occurred likely contained “dangerous goods and chemicals”.

Others showed glass blown out of buildings kilometres away from the epicentre of the explosion.

The cause of the explosion was not immediately clear.

It coincided with Iran beginning a third round of nuclear talks with the United States in Oman.

“The source of this incident was the explosion of several containers stored in the Shahid Rajaee Port wharf area,” a local crisis management official told state TV.

“We are currently evacuating and transferring the injured to medical centres.”

The semi-official Tasnim news agency posted footage of injured men lying on the road being tended to amid scenes of confusion.

State TV said: “Negligence in handling flammable materials was a contributing factor” in the explosion.

Oil facilities were not affected by the blast, the National Iranian Petroleum Refining and Distribution Company said.

“The explosion and fire in Shahid Rajaee Port have no connection to refineries, fuel tanks, distribution complexes and oil pipelines related to this company,” the statement said.

The large blast shattered windows within a radius of several kilometres, Iranian media said, with footage shared online showing a mushroom cloud forming following the explosion.

Fars news said the blast was heard in Qeshm, an island 26 kilometres south of Bandar Abbas.

In 2020, computers at the same port were hit by a cyberattack that caused massive backups on waterways and roads leading to the facility.

The Washington Post had reported that Iran’s arch-foe Israel appeared to be behind that incident as retaliation for an earlier Iranian cyberattack.

There was no immediate comment from Israeli military or Prime Minister Benjamin Netanyahu’s office when asked for comment on whether Israel was in any way involved in the explosion.

- with Reuters, AP