TEHRAN -- At least 25 people were killed and 800 others injured in a huge explosion at a port on Saturday in Iran's southern province of Hormozgan, media reported Sunday.

The exact cause of the incident has not been determined yet, the official news agency IRNA said.

The explosion occurred at the Port of Shahid Rajaee in the provincial capital Bandar Abbas, after which rescue teams were immediately dispatched to the scene, and all port activities were suspended, the semi-official Tasnim news agency reported.

In remarks to the semi-official Fars news agency on Sunday, Jalal Maleki, spokesman of the Tehran Fire Department, said the massive fire resulting from the blast had been almost contained, although there were still scattered flames, which he described as "not worrisome."

Ahmad Pouyafar, governor of Bandar Abbas, announced on Saturday that all educational centers across the city would be closed on Sunday due to the explosion and consequent air pollution.

Hossein Zafari, spokesperson for the National Disaster Management Organization, told Fars that chemical materials in a container at the port may have caused the blast.

However, the Iranian government's spokeswoman Fatemeh Mohajerani warned against any "hasty speculations" about the cause of the incident before relevant authorities complete the investigations.

What had been confirmed so far was that there were containers, probably with chemical materials, at a corner of the port, she added.

In a post on X, Iranian President Masoud Pezeshkian extended sympathy over the victims of the explosion, announcing that he had issued a directive for the investigation of the blast and its cause.

He added that Iran's Interior Minister Eskandar Momeni had been dispatched to the province to ensure necessary coordination and address the condition of the injured.

Following the incident, many countries, as well as international organizations and groups, extended condolences to the Iranian people and government.

Pakistani Prime Minister Shehbaz Sharif on Saturday expressed deep sorrow and grief over the losses caused by the explosion, according to the Prime Minister's Office.

"We stand with the Iranian government and people in this hour of grief and sorrow," Sharif said, while praying for the swift recovery of those injured in the incident.