A huge explosion, likely caused by the detonation of chemical materials stored at Iran's largest port, Bandar Abbas, killed at least four people and injured more than 500, Iranian state media reported.
The explosion, which hit the Shahid Rajaee section of the port, comes at a time when Iran launched a third round of nuclear talks with the United States in Oman, however there is no immediate indication of a link between the two events, Reuters reports.
Hossein Zafari, a spokesman for Iran's crisis management organization, blamed the explosion on poor storage of chemicals in containers at Shahid Rajaee.
"The cause of the explosion was the chemicals inside the containers," he told Iran's ILNA news agency.
"Previously, the Director General of Crisis Management had given warnings about this port during their visits and had pointed out the possibility of danger," Zafari said.
However, an Iranian government spokesman said that although chemicals had most likely caused the explosion, it was not yet possible to determine the exact cause.
Iran's official news channels broadcast images of a large cloud of black and orange smoke rising over the port after the explosion, and an office building with broken doors and papers and garbage scattered around.
Bandar Abbas is Iran's largest port and handles most of its containers in transit.
The explosion shattered windows within a radius of several kilometers and was heard in Qeshm, an island 26 kilometers south of the port, Iranian media said.
The semi-official Tasnim news agency posted images of wounded men lying in the street being tended to amid scenes of confusion.
State television previously reported that poor handling of flammable materials was a "contributing factor" in the explosion. A local crisis management official told state television that the explosion occurred after several containers stored at the port exploded.
As emergency workers tried to put out the fires, port customs officials said trucks were being evacuated from the area and that the container yard where the explosion occurred likely contained “dangerous goods and chemicals.” Activities at the port were halted after the explosion, officials said.