TEHRAN (AFP) — Firefighters have brought under control a blaze at Iran’s main port, following a deadly explosion blamed on negligence, authorities in the Islamic republic said.

The explosion, heard dozens of kilometers away, hit a dock at the southern port of Shahid Rajaee on Saturday.

At least 70 people were killed and more than 1,000 others suffered injuries in the blast and ensuing fire, which also caused extensive damage, state media reported.

Red Crescent official Mokhtar Salahshour told the channel late Monday that the fire had been “contained” and a clean-up was under way.

State television aired live footage on Tuesday showing thick smoke rising from stacked containers.

Iran’s customs authority said port operations had returned to normal, according to the IRNA news agency.

The port of Shahid Rajaee lies near the major coastal city of Bandar Abbas on the Strait of Hormuz, a waterway through which one-fifth of global oil output passes.

Hormozgan provincial governor Mohammad Ashouri ruled out sabotage.

“The set of hypotheses and investigations carried out during the process indicated that the sabotage theory lacks basis or relevance,” he told state television late Monday.

The port’s customs office said the blast may have started in a depot storing hazardous and chemical materials.

Interior Minister Eskandar Momeni said there were “shortcomings, including noncompliance with safety precautions and negligence.”

A committee assigned to investigate the blast cited similar factors as the likely cause.

Smoke, then fireball

CCTV images on social media showed it began gradually, with a small fire belching orange-brown smoke among a few containers stacked outside, across from a warehouse.

A small forklift truck drives past the area and men can be seen walking nearby.

About one minute after the small fire and smoke become visible, a fireball erupts as vehicles pass nearby, with men running for their lives.

President Masoud Pezeshkian visited hospitals treating the wounded on Sunday in the nearby city of Bandar Abbas.

Since the explosion, authorities have ordered all schools and offices in the area closed, and have urged residents to avoid going outside “until further notice” and to use protective masks.

The New York Times quoted a person with ties to Iran’s Islamic Revolutionary Guard Corps, speaking on condition of anonymity to discuss security matters, as saying that what exploded was sodium perchlorate — a major ingredient in solid fuel for missiles.

Defense ministry spokesperson Reza Talaei-Nik later told state TV that “there has been no imported or exported cargo for military fuel or military use in the area.”