TEHRAN (Dispatches) -- A powerful 7.3 magnitude earthquake near the Iraq-Iran border killed over 400 people across both countries, sent residents fleeing their homes into the night and was felt as far away as the Mediterranean coast, authorities said Monday.
Iran's western Kermanshah province bore the brunt of the temblor Sunday night, with authorities saying the quake killed 407 people in the country and injured 6,700. Kermanshah is a rural, mountainous region where residents rely mainly on farming.
Teams of Iranian rescuers dug through rubble in a hunt for survivors. Many people would have been at home when the quake hit.
As dusk approached on Monday, tens of thousands of Iranians were forced to sleep outside in the cold for a second night as authorities scrambled to provide them with aid.
Some had spent Sunday night outdoors after fleeing their homes in the mountainous cross-border region, huddling around fires at dawn as authorities sent in help.
"People's immediate needs are firstly tents, water and food," said the head of the Islamic Revolution Guards Corps, Major General Muhammad Ali Jafari.
"Newly constructed buildings... held up well, but the old houses built with earth were totally destroyed," he told state television during a visit to the affected region.
Hundreds of ambulances and dozens of army helicopters joined the rescue effort after Leader of the Islamic Revolution Ayatollah Seyyed Ali Khamenei ordered the government and armed forces to mobilize "all their means".
President Hassan Rouhani was scheduled to tour earthquake-damaged areas Tuesday. Authorities announced three days of mourning in Kermanshah province.
Officials said they were setting up relief camps for the displaced. Iran's emergency services chief Pir Hussein Koolivand said landslides had cut off roads to affected villages, impeding the access of rescue workers.
But by late afternoon, officials said all the roads in Kermanshah province had been re-opened, although the worst-affected town of Sar-e Pol-e Zahab remained without electricity.
Officials said 22,000 tents, 52,000 blankets and tonnes of food and water had been distributed. The official IRNA news agency said 30 Red Crescent teams had been sent to the quake zone.
After initially pinning the quake's epicenter inside Iraq, the USGS then placed it across the border in Iran on Monday morning. Iran's Sar-e Pol-e Zahab, home to some 85,000 people close to the border, was the worst hit with at least 236 dead.
At dawn, buildings in the town stood disfigured, their former facades now rubble on crumpled vehicles.
In an open space away from wrecked housing blocks, men and women, some wrapped in blankets, huddled around a campfire. Iranian media reported that a woman and her baby were pulled alive from the rubble.
The towns of Eslamabad and Qasr-e Shirin were also affected, while the tremor shook several western Iranian cities including Tabriz.
Some 259,000 people live in the region, according to the most recent census. State television showed tents, blankets and food being distributed in areas struck by the temblor.
In neighboring Dalahoo County, several villages were totally destroyed, an official told Tasnim agency.
The quake struck at 9:48 p.m. Iran time, just as people began retiring for the night. It could be felt on the Mediterranean coast, some 660 miles (1,000 kilometers) away.
The earthquake struck 23.2 kilometers (14.4 miles) below the surface, a shallow depth that can amplify damage. Magnitude 7 earthquakes can be highly destructive.
Iranian social media and news agencies showed images and videos of people fleeing their homes. More than 100 aftershocks followed.
Kokab Fard, a 49-year-old housewife in Sarpol-e-Zahab, said she fled empty-handed when her apartment complex collapsed. "Immediately after I managed to get out, the building collapsed," Fard said. "I have no access to my belongings."
Reza Muhammadi, 51, said he and his family ran out into the alley after the first shock. "I tried to get back to pick up some stuff but it totally collapsed in the second wave," Muhammadi said.
The ILNA news agency said at least 14 provinces in Iran had been affected by the earthquake. Behnam Saeedi, a spokesman for the country's crisis management headquarters, told two news agencies that casualty figures stood at 407 killed and 6,700 injured.
In Iraq, Prime Minister Haider al-Abadi issued a directive for the country's civil defense teams and "related institutions" to respond to the natural disaster. Brig. Gen. Saad Maan, an Interior Ministry spokesman, gave the casualty figures for Iraq.
The quake could be felt across Iraq, shaking buildings and homes from Erbil to Baghdad, where people fled into the streets of the capital.
Amina Muhammad, who survived the quake in Darbandikhan, Iraq, said she and her sons escaped their home as it collapsed around them.
"I think it was only God that saved us," she said. "I screamed to God and it must have been him who stopped the stairs from entirely collapsing on us."
The Iraqi city of Halabja, closest to the epicenter, was the target of a 1988 chemical attack in which Saddam Hussein's troops killed some 5,000 people with mustard gas — the deadliest chemical weapons attack ever against civilians.
Iraqi seismologist Abdul-Karim Abdullah Taqi, who runs the earthquake monitoring group at the state-run Meteorological Department, said the main reason for the lower casualty figure in Iraq was the angle and the direction of the fault line. He said the Iraqi geological formations were better able to absorb the shocks.
However, the temblor caused visible damage to the dam at Darbandikhan, which holds back the Diyala River.
"There are horizontal and vertical cracks on the road and in the body of the dam, and parts of the dam sank lower," said Rahman Hani, the director of the dam.
Turkey dispatched emergency aid to northern Iraq as officials expressed their "deep sadness" at the tragedy. Prime Minister Binali Yildirim said his country took immediate action to provide medical and food aid to northern Iraq.
Kerem Kinik, the Turkish Red Crescent's vice president, told The Associated Press from Habur border crossing that 33 aid trucks were en route to the northern Iraqi city of Sulaimaniyah, carrying 3,000 tents and heaters, 10,000 beds and blankets as well as food.
A Turkish military cargo plane arrived in Iraq as the official Anadolu news agency reported multiple dispatches by Turkey's disaster agency. Ankara also said it would help Iran if Tehran requests assistance.
Relations between Iraq's semi-autonomous Kurdish region and Turkey were strained following the Iraqi Kurds' September independence referendum.
Turkey's President Recep Tayyip Erdogan said his country stands with the region in difficult times and wished the Iraqi and Iranian people a speedy recovery.
Speaking en route to Sochi, Russia, Erdogan said a convoy of 50 aid trucks has crossed the border into Iraq. Pakistan also extended its condolences for the loss of life and injuries suffered by "our Iranian and Iraqi brethren."
Iran sits on many major fault lines and is prone to near-daily quakes. In 2003, a magnitude 6.6 earthquake flattened the historic city of Bam, killing 26,000 people. The last major casualty earthquake in Iran struck in East Azerbaijan province in August 2012, killing over 300 people.