Iranian authorities have not said what caused the massive explosion at the port of Bandar Abbas on Saturday, killing at least 28 people, amid unconfirmed reports of the possible presence of a chemical used to make missile propellant.

The death toll from a powerful explosion at Iran's biggest port of Bandar Abbas has risen to at least 40, with more than 1,200 people injured, state media reported on Sunday, as firefighters worked to fully extinguish the fire.

In Iran, mourning is turning to anger after a huge blast at its largest commercial port killed at least 40 people and injured more than 1,000. The explosion happened on Saturday morning at Shahid Rajaee port. Many people rushed to hospitals up and down the country to give blood.