Over 400 people have been killed in Iran and Iraq, after a powerful magnitude-7.3 earthquake hit the region.
At least 407 people were killed in Iran, said Iran's National Disaster Management Organisation spokeman Behnam Saeedi on state television. A further 6,700 people have been injured.
Officials expect the casualty toll to rise, when search-and-rescue teams reach remote areas of Iran.
A quake registering a magnitude between 7 and 7.9 can inflict widespread and heavy damage. Many houses in rural areas of Iran are made of mud bricks that can crumble easily in a quake.
The earthquake was felt in several provinces of Iran, but the hardest-hit province was Kermanshah, which has announced three days of mourning.
More than 142 of the victims were in Sarpol-e Zahab county in Kermanshah, about 15 km from the Iraq border.
The main hospital of the capital of the county was severely damaged and could not treat hundreds of injured people who were taken there, said the head of the Iranian emergency services, Pirhossein Koulivand.
The US Geological Survey said the quake measured magnitude 7.3. An Iraqi meteorology official put its magnitude at 6.5, with the epicentre in Penjwin in Sulaimaniyah province of the Kurdistan region, close to the main border crossing with Iran.
Kurdish health officials said at least four people were killed in Iraq and at least 50 injured.
The quake was felt as far south as Baghdad, where many residents rushed from their houses and tall buildings, when tremors shook the Iraqi capital.
"I was sitting with my kids having dinner and suddenly the building was just dancing in the air," said Majida Ameer, who ran out of her building in the capital's Salihiya district with her three children.
"I thought, at first, that it was a huge bomb, but then I heard everyone around me screaming 'Earthquake!'"
Similar scenes unfolded in Erbil, the capital of the Kurdistan Region, and across other cities in northern Iraq, close to the quake's epicentre.
Iran sits astride major fault lines and is prone to frequent tremors. A magnitude 6.6 quake on December 26 devastated the historic city of Bam, 1000 km southeast of Tehran, killing about 31,000 people.
On the Iraqi side, the most extensive damage was in the town of Darbandikhan, 75 km east of the city of Sulaimaniyah, in the semi-autonomous Kurdistan Region.
More than 30 people were injured in the town, according to Kurdish Health Minister Rekawt Hama Rasheed.