Oman, April 26 -- A massive explosion and subsequent fire rocked Iran's Shahid Rajaei port in the south of the country on Saturday, reportedly linked to a chemical shipment used in missile propellants.

The blast claimed the lives of four people and left more than 500 injured, AP reports.

The incident unfolded as Iranian and US officials met in Oman for the third round of discussions concerning Tehran's fast-advancing nuclear programme.

While Iranian authorities did not directly suggest the explosion resulted from an attack, Foreign Minister Abbas Araghchi, leading Iran's negotiation team, noted on Wednesday, "Our security services are on high alert given past instances of attempted sabotage and assassination operations designed to prov...