Russian President Vladimir Putin ordered emergency assistance to Iran following a massive explosion Saturday at the Shahid Rajaee port complex near Bandar Abbas, Iran's largest port, which killed at least 28 people and injured more than 1,000, according to Iranian state media.

The Kremlin said Putin conveyed "words of sincere sympathy and support to the families of the victims, as well as his wishes for a recovery to all those injured." Russia's emergency ministry confirmed it would dispatch a Beriev Be-200 amphibious aircraft, designed for firefighting, and an Ilyushin Il-76 military transport plane to assist Iranian authorities.

Iranian President Masoud Pezeshkian traveled to Bandar Abbas, approximately 20 miles west of the port, to oversee the investigation and emergency response. With fires still burning nearly 24 hours after the blast and thick smoke polluting the area, authorities closed schools and offices in the city and urged residents to remain indoors and use protective masks.

Initial footage broadcast by Iranian media showed a localized fire breaking out in a container around midday before spreading rapidly. Within minutes, a massive explosion occurred, knocking out surveillance cameras. Officials have yet to issue a formal explanation for the blast, though growing reports suggest that improperly stored chemicals under high temperatures may have triggered the incident.

The Tehran prosecutor's office has filed charges against several media outlets amid speculation that the explosion might have been an act of terrorism or a military error. However, officials stressed that early indications point to an accident.

Concerns have surfaced over safety practices at the port, with allegations that inspections related to chemical storage had been outsourced, potentially weakening enforcement of health and safety standards.

The explosion came as U.S. and Iranian negotiators resumed talks in Muscat, Oman, aiming to reach a new agreement on Iran's nuclear program in exchange for easing American sanctions. Iran's foreign ministry described the ongoing discussions as serious, practical and more detailed than previous rounds, with another meeting scheduled for the coming week.