At least four people are dead and more 500 people are reported injured after huge explosion at an Iranian oil facility in , on the south coast, according to Iranian state media. The site, which is one of main oil facilities, could be seen in video footage engulfed in large plumes of smoke.

Emergency services working on the area have said "the port remains in a state of chaos". The cause of the explosion, at the Shahid Rajaee section of the port, remains unclear at this stage, but local media site Tasnim reports a fuel tank had "exploded for an unknown reason".

An Iranian government spokesperson said while it was likely chemicals caused the blast, it was not yet possible to determine how.

Local media footage showed confused scenes in the aftermath, with men lying on the ground and the uninjured attempting to provide first aid to those in need.

A spokesperson for the country's emergency services said that 516 people are known to have been injured.

Mehrdad Hasanzadeh, a provincial disaster management official, told Iranian state TV that emergency services were attempting to make their way to the site of the explosion, while others are attempting to safely evacuate it.

Efforts are still ongoing to extinguish fires on the site with the explosion believed to have been heard as far away as Qeshm, an island 26 kilometres (16 miles) south of Bandar Abbas.

Iranian President Masoud Pezeshkian has expressed "deep regret and sympathy" for victims of the blast and has announced a government probe into what happened.

Rajaei port is around 650 miles southeast of Iran's capital, Tehran, on the Strait of Hormuz, the narrow mouth of the Persian Gulf through which 20% of all oil traded passes.

The blast comes as Iran prepares to open talks on a , for the third round of negotiations over Tehran's rapidly advancing nuclear program.

There is no idication currently of a link between the two events, as per Reuters.

, who is in Rome for the has warned that Iran "cannot be allowed to have a nuclear weapon."