A powerful earthquake struck western Turkey early today, killing over 1,000 people and injuring more than 5,000 in at least four other cities.
The death toll stood at 1,173 at 1600 GMT, according to the state-run Anatolian news agency.
Prime minister Bulent Ecevit was close to tears as he visited towns of the western Marmara region where the earthquake destroyed hundreds of apartment buildings. Thousands were injured or crushed as their homes collapsed under the force of the earthquake, which registered at least 6.7 on the Richter scale.
"The loss is huge," Mr Ecevit told state television in a trembling voice. "It is the biggest natural disaster I have witnessed. May Allah help our state and our people."
The US voiced sympathy and offered help. "Our thoughts and prayers are with the Turkish people today," said David Leavy, spokesman for the US national security council. He said general Henry Shelton, chairman of the Pentagon's joint chiefs of staff, was in Turkey and had offered to his Turkish counterparts US assistance such as helicopters, tents and blankets from American bases there.
In addition, the US agency for international development was dispatching a search-and-rescue advisory team from Fairfax, Virginia, and Miami to provide help in digging out survivors from the rubble.
The earthquake hit at 0002 GMT, flattening buildings in towns and cities around the eastern end of the Marmara Sea. Many of the dead were crushed in their sleep. President Suleyman Demirel said that he feared the worst from the devastation.
"I think the death toll will be high. An earthquake of 6.8 on the Richter scale is a major one," the Anatolian news agency quoted Mr Demirel as saying. "God willing we will not find so bad a picture as we feared."
A series of aftershocks, many of them serious tremors in their own right, has apparently subsided and attention has focused on efforts to free those trapped under the rubble. Mr Ecevit thanked the international community for offers of aid but warned them of the scale of the disaster and its devastating impact on transport and communications.
"This morning, as soon as the quake was heard of, friendly countries offered us help. We thank them.
Their rescue teams are expected to arrive tonight but we have difficulty in getting them to the disaster areas," he said. Turkey says it can shelter and feed the thousands of homeless but asked for specialist teams with sniffer dogs that can find and rescue those trapped under the rubble. Mr Ecevit called on rescuers to refrain from using bulldozers to clear the wreckage, warning such powerful intervention might kill those trapped in fragile air pockets.
"Some of our citizens who lost their loved ones under wreckage demand heavy machinery to clear it and save their relatives. But if we do this we can lose more people than we save. So we have to be patient and wait," he said.
It was the worst earthquake to strike western Turkey and authorities fear that the toll could rise sharply. Rescuers dug with everything from bare hands to picks and shovels. In the hard-hit town of Golcuk, the mayor said 500 buildings housing 20,000 families had collapsed.
"There could be as many as 10,000 people under the debris," Mayor Ismail Baris said.
Private NTV television said the dead included 160 sailors who perished in the collapse of two navy buildings in Golcuk, near the industrial city of Izmit, some 81 miles (130 kilometres) southeast of Istanbul. Hundreds of people were also reported injured in the western cities of Bursa, Eskisehir, Bolu and Yalova.
"We need everything: field hospitals, kitchens, tents and ambulances," governor Nihat Ozgol said in Yalova, where 90 people died. A dozen hours after the quake, many victims remained buried in the rubble of their homes.
"They can hear the voices of my mother and sister but know nothing about my father and brother," said Arsu Yilmaz as rescue workers dug at a building in Istanbul's Avcilar district. Authorities said at least 156 were killed in Istanbul alone.
Thousands of buildings collapsed in the worst-hit cities and towns. Roads were severely damaged in Istanbul and parts of western Anatolia. Ahmet Cafoglu, head of the Turkish standards institute, blamed shoddy construction for the vast damage and huge loss of life.
The energy ministry said two gas-fired power plants were damaged as well as several power transmission lines. There were blackouts in parts of the western Anatolia, including Istanbul. Water service was also out in Istanbul, a heavily crowded metropolis of 12 million people, and other towns. Condolences and offers of help poured in from around the world.
Besides the US, France dispatched a team of 60 rescue workers and six sniffer dogs, along with 15 tons of equipment. The German Red Cross said it was also sending a rescue team with dogs. Switzerland as well was sending in dogs trained to sniff out trapped survivors. Iran and Israel also offered help.
US energy secretary Bill Richardson, in Istanbul for talks on Caspian oil and gas pipeline projects, called the earthquake a frightening 45 seconds worth of very violent shaking. "We were able to observe the darkness of the earthquake, people streaming into the streets, lights going out in Istanbul," he said. "I can tell you having experienced an earthquake before, in Mexico, this was a very strong earthquake."
In Izmit, NTV said overwhelmed hospitals were turning away people with minor injuries and treating people on the pavement. Medical workers broke windows of pharmacies to get supplies for hospitals, it said. Tanks at a state oil refinery in Izmit caught fire, but officials later said the damage was minor.
Thousands of people took to the streets in panic when the quake struck at 3 a.m. local time and spent the night outdoors.
More than 250 aftershocks followed, the Kandilli Observatory said. Authorities warned people to stay out of damaged buildings, even if the damage seemed minor.
The US geological survey's national earthquake information centre in Golden, Colorado, said the quake had a magnitude of 7.8, which made it nearly as powerful as the devastating San Francisco quake of 1906. It said the epicentre at about 45 miles (70 kilometres) southeast of Istanbul, and about 35 miles (50 kilometres) north of Bursa.
"We saw the floor move, we all ran out of the house," said Ramazan Aydeniz, sitting in front of the Istanbul ice cream shop where he works. "The kids, the elders were all panicked."
There was no damage to historical sites in Istanbul and no foreigners were injured, the government said. Tens of thousands of tourists visit sites such as the Blue Mosque, the nearly 1,500-year-old Saint Sophia or Topkapi Palace, the seat of the Ottoman sultans each summer.
"We stayed in bed while everybody else got out. Then there were aftershocks and they asked us to evacuate the hotel," said Fiona Spearman, a tourist from Oxford.
Much of Turkey sits on an earthquake-prone belt known as the Anatolia fault. Izmit, also known as Kocaeli, also sits on the fault line. A 6.3-magnitude quake hit Turkey on June 27, 1998, killing 144 people and injuring over 1,500 in and around the southern city of Adana.
Hotline for British tourists:
0171 839 1010
Useful links:
The Republic of Turkey: Information from the Turkish embassy, Washington
Turkish ministry of foreign affairs
Hurriyet: Turkish newspaper (site currently very busy)
United States Geological Survey: earthquake information
National Earthquake Information Centre (US)
CIA Factbook: Turkey
Earthquakes: basic information
Seismic safety
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Map of the affected area