A 7.3-magnitude earthquake that struck the mountainous Iran-Iraq border on Sunday left over 200 people dead and thousands others injured as the quake triggered landslides and house collapses.
The quake hit 30 kilometres southwest of Halabja in Iraqi Kurdistan at around 9.20 pm, when many people would have been at home, making it deadlier.
US Geological Survey said the quake measured magnitude 7.3 while Iraqi meteorology department official put its magnitude at 6.5 with the epicentre in Penjwin in Sulaimaniyah province in the Kurdistan region close to the main border crossing with Iran.
Twitter images showed panicked people fleeing a building in Sulaimaniyah, in northern Iraq, while images from nearby town of Darbandikhan showed collapsed walls and concrete structures.
Television reports said electricity was cut off in several Iranian and Iraqi cities and thousands left their homes to seek safety in the open spaces amidst fears of aftershocks while rescuers have stepped up efforts to find dozens trapped under the rubble.
Tremours were felt as far back as Diyarbakir, the southern-most city of Turkey, although there were no immediate reports of damage or casualties in the city.
The worst-hit towns in Iran were Qasr-e Shirin in Kermanshah and Azgaleh, about 40 kilometres northwest, Iranian news agency IRNA said.
Iran's emergency services chief Pir Hossein Koolivand said it was "difficult to send rescue teams to the villages because the roads have been cut off... there have been landslides."
In Iraq, officials said six people died and about 150 others were injured in Sulaimaniyah province,where some damage to property was also reported.
"Four people were killed by the earthquake" in Darbandikhan, AFP quoted the town's mayor Nasseh Moulla Hassan as saying.
In Kalar, about 70 kilometres south of Darbandikhan., A child and an elderly person were killed and 105 people were injured, according to the director of the hospital in the town.
In Iran, the hardest hit province was Kermanshah. More than 97 of the victims were in the town of Sarpol-e Zahab in Kermanshah, about 15 kilometres (10 miles) from the Iraq border. The main hospital of the town, which was also severely damaged, was struggling to treat hundreds of injured people, state television reported.
Kurdish health officials also said at least four people were killed in Iraq and at least 50 were injured.
Television reports said there was no electricity in several Iranian and Iraqi cities that made relief measures difficult.
''The night has made it difficult for helicopters to fly to the affected areas and some roads are also cut off... we are worried about remote villages,'' Iranian interior minister Abdolreza Rahmani Fazli said in an interview on state television.
Many houses in rural parts of the province are made of mud bricks and are known to crumble easily in quake-prone Iran.
The Iranian armed forces have been deployed to help emergency services.
A quake registering a magnitude between 7 and 7.9 can inflict widespread and heavy damage.
Iran sits astride major fault lines and is prone to frequent tremors. A magnitude 6.6 quake on 26 December, devastated the historic city of Bam, 1,000 kilometres (600 miles) southeast of Tehran, killing about 31,000 people.