The death toll from a powerful explosion at Iran's biggest port of Bandar Abbas has risen to at least 28, with more than 700 people injured, state media reported on Sunday, as firefighters worked to fully extinguish the fire.

Saturday's blast, which officials say was probably caused by chemical materials, took place in the Shahid Rajaee section of the port - Iran's biggest container hub.

The force of the explosion shattered windows for several kilometres around Bandar Abbas, which is located near the strategic Strait of Hormuz, tearing metal shreds off shipping containers and badly damaging goods stored inside, state media reports said.

Iran's crisis management organisation said that of the 752 people who had received treatment for their injuries, 190 were still being treated in medical centres.

Visiting the scene, Interior Minister Eskandar Momeni told state TV 80% of the fire had been extinguished by Sunday morning and firefighting efforts would continue for a few more hours.

Some operations resumed in parts of Shahid Rajaee that were not affected by the fire or damage.

While chemical materials are thought to have been involved, the exact cause of the explosion is yet to be clarified.

President Masoud Pezeshkian has ordered an investigation.

Also Read: 18 killed, over 750 injured in blast at Iran’s Bandar Abbas port

A spokesperson for the country's crisis management organisation appeared on Saturday to blame the explosion on poor storage of chemicals in containers at Shahid Rajaee, adding that earlier warnings had highlighted potential safety risks.

Government spokesperson Fatemeh Mohajerani cautioned against "premature speculation".

The incident occurred as Iran began a third round of nuclear talks with the United States in Oman, but there was no indication of a link between the two events.

A series of deadly incidents has hit Iranian energy and industrial infrastructure in recent years, with many blamed on negligence.

They have included refinery fires, a gas explosion at a coal mine, and an emergency repair incident at Bandar Abbas that killed one worker in 2023.

Iran has blamed some other incidents on its arch-foe Israel, which has carried out attacks on Iranian soil targeting Iran's nuclear program in recent years and bombed the country's air defences in 2024.

Israel has indicated it is nervous about the outcome of US-Iran talks, demanding a full dismantlement of Iran's nuclear program.

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

Oil facilities were not affected by the blast, Iranian authorities said.