An enormous explosion struck the Shahid Rajaee Port in Bandar Abbas, southern Iran, on Saturday, leaving four dead and injuring at least 516 others, according to reports from Iranian state media.

The blast unfolded as Iran and the United States began a fresh round of nuclear talks in neighboring Oman. Authorities are still investigating the cause of the explosion, though preliminary information points to containers at the port being the source, a local official said.

Citing The Jerusalem Post, reports indicated that the explosion occurred close to a naval base operated by Iran’s Islamic Revolutionary Guard Corps (IRGC). Meanwhile, Israel’s military, the IDF, issued a statement denying any involvement in the incident.

Videos circulating on social media captured plumes of thick black smoke rising above the area. Footage also showed damaged buildings, wrecked vehicles, and civilians aiding the injured amidst the debris.

"A number of containers at Shahid Rajaee Port exploded, leading to the incident. Evacuation efforts and the transfer of injured individuals to medical centers are currently underway," a local crisis management official told Reuters.

Emergency teams quickly reached the scene, working to contain the situation and clear the site of people.

Shahid Rajaee Port serves as a key hub for Iran’s container shipping and is equipped with facilities for oil storage and petrochemical operations.

In an official statement, the National Iranian Petroleum Refining and Distribution Company (NIPRDC) assured that the explosion did not affect its oil-related infrastructure. "The explosion and subsequent fire at Shahid Rajaee Port are unrelated to the company's refineries, fuel storage, distribution centers, or pipelines," the statement read.

The timing of the incident comes as delicate negotiations are underway between Washington and Tehran. US special envoy Steve Witkoff and Iranian Foreign Minister Abbas Araghchi are leading their respective delegations in efforts to strike a new agreement aimed at restricting Iran’s nuclear activities — which Tehran maintains are peaceful — in return for lifting international sanctions.