An explosion at a residential building in the southern Iranian port city of Bandar Abbas on Saturday was caused by a gas leak, local fire chief Mohammad Amin Lyaghat said.

“The initial cause of the building accident in Bandar Abbas was a gas leak and buildup, leading to an explosion. This is the initial theory,” he told state television.

The blast killed at least one person and injured 14 others, local officials told Iranian news agencies. Investigations are ongoing, with authorities dismissing social media claims that a Revolutionary Guard navy commander was targeted in the incident as “completely false,” according to the semi-official Tasnim news agency.

Separate incidents were reported elsewhere in Iran on Saturday. In Ahvaz, near the Iraqi border, a gas explosion killed four people, state-run Tehran Times reported. Iranian media provided limited details, and officials could not be reached for further comment.

Two Israeli officials told Reuters that Israel was not involved in the explosions. The incidents come amid heightened tensions between Tehran and Washington over Iran’s nuclear program and a nationwide crackdown on protests, with U.S. President Donald Trump having warned of military action against the Islamic republic.

Earlier on Saturday, Iranian President Masoud Pezeshkian accused U.S., Israeli, and European leaders of exploiting the country’s economic problems, inciting unrest, and providing people with the means to “tear the nation apart.”

Bandar Abbas, home to Iran’s main container port, sits on the Strait of Hormuz, a key waterway handling about a fifth of the world’s seaborne oil. The city suffered a major explosion in April last year that killed dozens and injured more than 1,000 people, with an investigative committee attributing the blast to lapses in civil defense and safety measures.

The southern port city incidents occur against the backdrop of nationwide protests that erupted in December over economic hardship. At least 5,000 people were reported killed in the unrest, including 500 members of Iran’s security forces, officials told Reuters.