The blast occurred as Iran began a third round of nuclear talks with the United States in Oman. The cause wasn't immediately clear.

A huge explosion has occurred in the port city of Bandar Abbas in southwestern Iran, injuring 516 people, a spokesperson for the country’s emergency services has said.

The blast happened at the Rajaei port just outside of Bandar Abbas, a major facility for container shipments for the Islamic Republic that handles some 80 million tons of goods a year. Social media videos showed black billowing smoke after the blast.