Last updated 1 July 

The death toll from the suicide attack on Istanbul's Ataturk Airport has risen to 44. 

Twenty-fourTurkish citizens and 19 foreign nationals were among those killed, and 238 other people were injured, when three suicide bombers targeted the airport.

Turkish prime minister Binali Yildirim said the bombers arrived at the airport in a taxi and blew themselves up after opening fire on passengers, but there are conflicting accounts of the attack.

A Turkish official said authorities are going through CCTV footage and witness statements to establish a preliminary timeline and details of the attack, describing the investigation as "a jigsaw puzzle".

The Haber Turk newspaper reported that one attacker blew himself up outside the terminal, then two others opened fire at the point where the X-ray machines are.

It said one attacker was shot at while running amid fleeing passengers, then blew himself up at the exit. The third attacker went up one level to where the international departures terminal is, was shot by police and blew himself up.

Airport surveillance video posted on social media shows the moment of one blast, a huge ball of fire, and passengers fleeing in terror. Another appears to show an attacker, felled by a gunshot from a security officer, blowing himself up seconds later.

Watch: Police officer shoots bomber and escapes with seconds to spare

It was the latest in a series of attacks in Turkey in recent months which have scared away tourists and damaged the economy, which relies heavily on tourism.

As dawn broke over the destroyed terminal, workers began removing debris left by the blast. The airport has partially reopened but an information board inside showed that about one-third of scheduled flights had been cancelled, with a host of others delayed.

Speaking at the airport, Mr Yildirim said all initial indications suggest the Islamic State group, also known as Daesh, was behind the attack.

"The findings of our security forces point at the Daesh organisation as the perpetrators of this terror attack," he said.

"Even though the indications suggest Daesh, our investigations are continuing."

Turkey shares long, porous borders with Syria and Iraq, war-torn countries where IS controls large pockets of territory. Authorities have blamed IS for several major bombings over the past year, including on the capital Ankara, as well as attacks on tourists in Istanbul.

Turkey has stepped up controls at airports and land borders and deported thousands of foreign fighters, but has struggled to tackle the threat of IS militants while also conducting vast security operations against Kurdish rebels, who have also been blamed for recent deadly attacks.

The devastation at Istanbul's airport follows the March attack on Brussels Airport, where two suicide bombings ripped through check-in counters, killing 16 people. The Islamic State group claimed responsibility for that attack, as well as a subsequent explosion at a Brussels subway station that killed 16 more people.

Belgian prime minister Charles Michel said on Twitter: "Our thoughts are with the victims of the attacks at Istanbul's airport. We condemn these atrocious acts of violence."

Turkish airports have security checks at both the entrance of terminal buildings and then later before entry to departure gates.

Mr Yildirim called for national unity and "global co-operation" in combating terrorism.

"This (attack) has shown once again that terrorism is a global threat," he said. "This is a heinous planned attack that targeted innocent people."

He suggested that the attack was linked to what he said was Turkey's success against Kurdish rebels, as well as steps Ankara took on Monday towards mending strained ties with Israel and Russia.

"It is meaningful that this heinous attack came at a time when we have become successful in the fight against separatist terrorism... and at a time when we started a process of normalising ties with our neighbours," he said.

Eyewitness Adam Keally, from Boston, said he heard gunfire followed by several explosions, then saw people "very badly injured".

Hevin Zini, 12, had just arrived from Dusseldorf, Germany, with her family and was in tears.

"There was blood on the ground," she said. "Everything was blown up to bits... if we had arrived two minutes earlier, it could have been us."

Two South African tourists, Paul and Susie Roos from Cape Town, were at the airport and due to fly home at the time of the explosions.

"We came up from the arrivals to the departures, up the escalator when we heard these shots going off," Mr Roos said. "There was this guy going roaming around, he was dressed in black and he had a handgun."

US President Barack Obama spoke by telephone with Erdogan earlier today, a White House spokesman said.

The White House will offer "any support that the Turks can benefit from as they conduct this investigation and take steps to further strengthen the security situation in their country," they said.

Russian President Vladimir Putin is expected to offer his condolences in a telephone call later with Turkish counterpart Recep Tayyip Erdogan - their first conversation in seven months. Russia froze its ties with Turkey in response to the shooting down of one of its military jets last November.

Mr Putin's spokesman Dmitry Peskov said the Ataturk attack is "just another reminder of the importance of joint efforts to fight our common threat - terrorism".

Israel's president Reuven Rivlin has told Mr Erdogan that their countries' new reconciliation pact will help with joint efforts to combat such attacks.

In a condolence letter, he said Israel is willing to help Turkey recover from the attack, and to work together to thwart future attacks.

"I take this opportunity to welcome the chance to renew our good relationship especially because our strengthened dialogue will greatly aid in our joint efforts against this threat, and because it sends a strong message to the terrorists that we will stand untied against hatred," Mr Rivlin said in the letter.

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