At least 36 people have been killed after three suicide bombers opened fire before blowing themselves up at Istanbul’s main airport.
Officials said the number of dead is likely to rise to 50, while Turkey’s prime minister said Islamic State militants appeared to have carried out the attack, which left almost 150 people injured.
Witnesses said one attacker opened fire in the departures hall with an automatic rifle, sending passengers diving for cover, before all three blew themselves up in or around the arrivals hall a floor below.
Dead bodies could be seen scattered in the road just outside the terminal building, while video emerged showing a police officer shooting one of the attackers, then fleeing moments before they detonate their suicide vest.
Foreign Office officials said they were “urgently seeking further information” after Turkey said the majority of those killed were Turkish, but foreigners were also among the victims.
Speaking in Brussels, David Cameron described the attack as “hideous”.
The attack at Istanbul Ataturk – Europe’s third busiest airport – is one of the deadliest in a series of suicide bombings in Turkey, which has struggled to contain the conflict in neighbouring Syria and an insurgency by Kurdish militants.
Paul Roos, 77, described seeing one of the attackers “randomly shooting” in the departures hall.
Mr Roos, a South African returning to Cape Town with his wife after a holiday in southern Turkey, said: “He was just firing at anyone coming in front of him. He was wearing all black. His face was not masked. I was 50 metres away from him.
“We ducked behind a counter but I stood up and watched him. Two explosions went off shortly after one another. By that time he had stopped shooting.”
A woman named Duygu, who was at passport control having just arrived from Germany, said she threw herself onto the floor with the sound of the explosion. Several witnesses also reported hearing gunfire shortly before the attacks.
“Everyone started running away. Everywhere was covered with blood and body parts. I saw bullet holes on the doors,” she said outside the airport.
Turkey’s President Tayyip Erdogan said the attack should serve as a turning point in the global fight against militant groups.
He said: “The attack, which took place during the holy month of Ramadan, shows that terrorism strikes with no regard for faith and values.
“The bombs that exploded in Istanbul today could have gone off at any airport in any city around the world.”
Scheduled flights from the airport were stopped and passengers were taken to hotels, Turkish Airlines said, while some flights to the airport were diverted.
British Airways passengers on flight BA680 from London Heathrow to Ataturk were returned to the UK in the wake of the blasts.
The flight had been due to land at around 11.40pm (9.40pm UK time), shortly after the explosions.
According to the Dogan news agency, a plane carrying Albanian Prime Minister Edi Rama was landing at the airport when the attack happened. He and his entourage were taken to an official residence.
Turkey has suffered a spate of bombings this year, including two suicide attacks in tourist areas of Istanbul blamed on Islamic State, and two car bombings in the capital, Ankara, which were claimed by a Kurdish militant group.
In the most recent attack, a car bomb ripped through a police bus in central Istanbul during the morning rush hour, killing 11 people and wounding 36 near the main tourist district, a major university and the mayor’s office.