Four people died and at least 516 were injured in an explosion at southwestern Iran's power of Badar Abbas, according to state media.

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

At least five people have been killed and 700 injured in a massive explosion at one of Iran's key ports, state media is reporting. The suspected chemical blast took place at Shahid Rajaee, the country's largest commercial port, near the southern city of Bandar Abbas on Saturday morning.