Situated on or near several fault lines, Turkey is one of the world's most active earthquake zones.

Most of the country is located on the Anatolian tectonic plate, which sits between two major plates - the Eurasian and African - and another minor one, the Arabian. As the two large plates shift, Turkey is essentially squeezed, experts say.

That means quakes and tremors are a fairly common experience. The country's Disaster and Emergency Management Authority (AFAD) recorded over 22,000 in 2022.

And many are deadly - the worst on record a 7.6 magnitude earthquake which struck İzmit in 1999, killing more than 17,000 people.

The UK-based Syrian Observatory for Human Rights has updated its preliminary death toll to 320 for the whole of Syria shortly before 07:00 GMT.

Meanwhile, Syria's President Bashar Assad chaired an emergency meeting early this morning.

Dutch PM Mark Rutte has announced a Dutch search and rescue team will join the hunt for survivors in Turkey and Syria. In a tweet, he also shared his condolences to Turkey's president Erdogan, saying: "Thoughts are with all victims of this serious natural disaster."

The Greek PM, Kyriakos Mitsotakis, said that Greece would also be "mobilising its resources" and assist the affected areas "immediately".

The leaders of Serbia and Sweden have also promised to send help to the region.

Locals have described their fear and confusion as the powerful quake hit in the early hours of the morning.

"Paintings fell off the walls in the house," Samer, a resident of Syrian capital Damascus told Reuters.

"I woke up terrified. Now we're all dressed and standing at the door."

In the Turkish city of Gaziantep, Erdem described feeling shaken around "like a baby in a crib".

"I have never felt anything like it in the 40 years I've lived," he told Reuters over the phone.

"Everybody is sitting in their cars, or trying to drive to open spaces away from buildings."

"I imagine not a single person in Gaziantep is in their homes now."

Image source, Getty Images

Another man in Pazarcık said his family had woken to powerful shocks, and faced a cold and tense wait for sunrise to survey the damage.

"There are destroyed buildings around me, there are houses on fire. There are buildings that are cracking. A building collapsed just 200 meters away from where I am now," Nihat Altundağ said, in a report by The Guardian, external.

“People are all outside, all in fear.”

A CCTV camera captured the moment the earth started shaking in Turkey during the early hours of the morning.

Image source, Reuters

If you're just joining us, welcome to our coverage. Here's what we know so far:

• More than 500 people have been killed in Turkey and Syria after the quake
• It could be Turkey's largest earthquake, Stephen Hicks, a seismologist at University College London, says
• There have been more than 40 aftershocks, according to Turkey’s Disaster and Emergency Management Authority
• Millions of Syrian refugees live close to the epicentre. Turkey is the world’s largest host of refugees with 3.7 million Syrians taking refuge in the country.
• Many people are still trapped under the rubble and the rescue operation could be hampered by bad weather

Israel has said it is prepared to help quake-ravaged Turkey. The country's foreign minister Eli Cohen said a swift aid programme a being prepared. Its defence minister Yoav Gallant said Israeli security forces stand ready to offer any assistance needed, Reuters reports.

Tremors from the quake were also felt in parts of Israel and the Palestinian territories.

The death toll in Turkey has risen to 284, with 2,323 people injured, Turkey's Vice President Fuat Oktay says.

Some have said this may be Turkey's largest earthquake on record - as strong as one that happened over 80 years ago.

Stephen Hicks, a seismologist at University College London, says the previous largest earthquake, also at magnitude 7.8, struck north-eastern Turkey in December 1939 and killed 30,000 people.

More recently, in January 2020, an earthquake of magnitude 6.7 hit the region around Elazığ, a city east of Turkey. It killed 41 people and injured over 1,600.

Raed Ahmed, head of Syria's National Earthquake Centre, told a state radio station that this is the "largest earthquake ever recorded in the centre's history." The centre was founded in 1995.

A tsunami alert for southern Italy has been lifted, the Italian civil protection said.

Overnight, the body advised people to move away from coastal areas and warned there was a risk of tsunami waves following the earthquake.

Train services on railways near the coast of southern regions were halted for around an hour on Monday morning, but have since resumed.

An update from the Syrian health ministry says 237 people have been killed in the country - across the government-held provinces of Aleppo, Latakia, Hama and Tartus.

More than 600 people are injured, the ministry says.

We don't yet know how many victims there have been in the rebel-held province.

One woman told the BBC she was convinced her family would die when the quake shook their 5th floor apartment in the southern Turkish city of Adana.

"I have never seen anything like this in my life. We swayed for close to one minute," Nilüfer Aslan said.

She described calling out to relatives in other rooms.

"[I said] 'There is an earthquake, at least let's die together in the same place'... It was the only thing that crossed my mind."

When the quake paused, Aslan fled outside - "I couldn't take anything with me, I'm standing outside in slippers" - to find that four buildings surrounding his own had collapsed.

More than 100 people have been killed and hundreds more wounded in Syria, state media is reporting.

The quake was felt along the country's west coast from Latakia to the capital Damascus.

It also hit opposition-held regions along the Syrian-Turkish border, where access to healthcare is limited and many live in dilapidated conditions.

A video shared online by the volunteer Syrian civil defence, the White Helmets, shows evacuation and first-aid operations underway in the dark in the region north of Aleppo.

Many residents are still trapped in rubble, local media is reporting. They are also urging citizens to help shuttle victims to hospitals.

Image source, Getty Images

Image source, Getty Images

Footage shows men trying to smash windows with bricks to save people trapped in collapsed buildings in central Turkey.

Özgül Konakçı, a 25-year-old who lives in Malatya, survived the earthquake but said the aftershocks and cold weather were worrying.

“Search and rescue efforts continue. It's very cold and it's snowing right now. Everyone is on the streets, people are confused about what to do. Just before our eyes, the windows of a building exploded due to aftershocks,” she told BBC Turkish.

Ms Konakci and her brother were sleeping on the sofa when the earthquake struck.

“We looked at each other and said, ‘Are you shaking?’ I looked at the lamp, it looked like it was going to collapse. As soon as we got my three-year-old nephew inside, we jumped out.”

Her building was damaged, she said. But nearby, five surrounding buildings collapsed.

She added that traffic in the city is congested as people were desperate to move away from the buildings amid fears of aftershocks.

The United States is "profoundly concerned" by the reports of the disaster, US national security advisor Jake Sullivan said.

US President Joe Biden has directed the country's international development agency to asses how it can help.

The tremor's damage has centred on southern Turkey and Syria, but it was also felt in nearby Lebanon, Gaza and Cyprus.

"I was writing something and just all of a sudden the entire building started shaking and yes I didn't really know what to feel," Mohamad El Chamaa, a student in the Lebanese capital Beirut, told the BBC.

"I was right next to the window so I was just scared that they might shatter. It went on for four-five minutes and it was pretty horrific. It was mind-blowing," he said.

Rushdi Abualouf, a BBC producer in the Gaza Strip, also said he felt about 45 seconds of shaking in the house he was staying in.

Turkey's disaster and emergency agency AFAD has put out an update saying 76 people have been killed there and 440 injured so far in the earthquake.

Forty-two people were killed and more than 200 injured in Syria due to the quake, according to the country's official news agency.

Syrian state media also reported a large number of buildings have collapsed in the province of Aleppo.

Image source, Getty Images

Turkey's President Recep Tayyip Erdogan has tweeted, sending his "best wishes" to all affected citizens.

"We hope that we will get through this disaster together as soon as possible and with the least damage," he said.

He said search and rescue teams were immediately dispatched to the areas affected by the quake, and other units were on alert.