The explosion produced a towering plume of dense, grey smoke from the Shahid Rajaee area of the port complex, with CNN-geolocated videos showing the aftermath, while the government suggested that the blast might be related to stored chemicals.

Iran’s Interior Minister, Eskandar Momeni, mentioned that six individuals are still unaccounted for as firefighters face challenges from high winds while attempting to control the blaze, according to Iranian media coverage.

No cause has been given for the explosion. A government spokeswoman, Fatemeh Mohajerani, said it would take some time to establish the cause “but so far what has been determined is that containers were stored in a corner of the port that likely contained chemicals which exploded.

She added: “But until the fire is extinguished, it’s hard to ascertain the cause.”

Iranian authorities have declared a state of emergency in the city of Bandar Abbas to safeguard citizens amid a “significant rise in air pollution”.

The Ministry of Health has mobilised health teams and implemented emergency measures to protect public health. Citizens are advised to stay indoors, avoid outdoor activities, and keep windows closed, according to official Iranian media.

A video distributed by the Mehr news agency showed surveillance footage of the moment of the explosion, which appears to have occurred in a warehouse at the port. Other footage showed helicopters dropping water at the site of the fire ignited by the explosion.

Debris was spread over a wide area and many buildings at the port complex were badly damaged, according to state media. Windows within a radius of several kilometres were shattered, they said.

Some reports said people were trapped in the wreckage of a building that was reduced to rubble.

The region’s governor, Mohammad Ashouri Taziani, said injured people were being transferred to Bandar Abbas medical centres. The port has been closed and maritime operations suspended, according to state media.

Iranian President Masoud Pezeshkian has ordered an investigation into the causes of the incident.

He wrote on X that the interior minister had been sent to the region to “examine the dimensions of the accident”.

State broadcaster IRIB said the explosion took place in the chemical and sulfur area of the port.

The incident has shocked the country and many were seen on Iran’s state-run Press TV lining up at a health centre to donate blood for the injured.

Shahid Rajaee is a large facility for container shipments, covering 2400 hectares. It handles 70 million tons of cargo annually, including oil and general shipping. It has nearly 500,000 square metres of warehouses and 35 shipping berths.