Iran has been struck by its most powerful earthquake for nearly 40 years, with tremors felt across Pakistan, India and the Middle East.
The epicentre of the 7.8 magnitude quake was near the south-east city of Khash, close to the Pakistani border, the US Geological Survey said.
Offices were evacuated in Abu Dhabi and tall buildings swayed in the Indian capital Delhi, witnesses said.
Iranian state TV says that no deaths have been confirmed.
Earlier reports from Iran suggested that 40 people had been killed.
At least five people died in Pakistan, near the border with Iran, hospital and local government officials said.
All communications to the region have been cut. The Iranian Red Crescent aid agency said it was sending 20 search-and-rescue teams with three helicopters to the area.
Quake felt hundreds of miles away
The earthquake struck in the mid-afternoon, in the province of Sistan Baluchistan, close to the cities of Khash, with a population of nearly 180,000, and Saravan, with 250,000.
Iran's Fars news agency was reporting that Saravan had suffered no serious damage.
The earthquake has been felt hundreds of miles away across the region of the Middle East. A BBC correspondent in Abu Dhabi said she was evacuated from her office.
Michael Stephens, a an office worker in Quatari capital Doha told the BBC: "I definitely felt the walls shaking. It lasted for about 25 seconds."
Mohammad Wazir, a BBC correspondent in Pakistan, says the quake was felt in the cities of Karachi and Quetta.
It's the second big earthquake to hit Iran in a week. On 10 April, a 6.3-magnitude quake in south-west Iran killed at least 37 people and wounded 850.