Istanbul Airport Attack: A Timeline from Turkish Officials of the Bombings That Killed 42

— -- The terrorists who killed dozens at a busy airport in Istanbul took advantage of the panic sparked when they opened fire at a security checkpoint to detonate their explosives, according to the Turkish prime minister.

The details from the prime minister and others from a Turkish official come as investigators begin to piece together the timeline of the attack at Istanbul's Ataturk International Airport, which left 42 dead and 238 wounded.

Turkey’s Prime Minister, Binali Yildirim, said today the attack, which took place around 10 p.m. Tuesday, began "when the terrorists couldn't pass the regular security system, when they couldn't pass the scanners, police and security controls," Yildirim said.

"They returned and took out their weapons out of their suitcases and opened fire at random at the security check," he added.

After that, the terrorists “took advantage of the panic created during the shoot out” before blowing themselves up, according to Yildirim.

Separately, a Turkish official outlined to ABC News how the attackers targeted three separate sections of the airport, with the source saying the third terrorist appeared to waiting for people to run outside towards him to donate the final bomb.

The first terrorist detonated a bomb in the arrival area before the X-ray machines, the official said.

The second terrorist then walked in during the chaos and detonated a bomb at the upper departure level, the official said.

The third terrorist, who was outside during the first two explosions, apparently waited for people to run outside and then blew himself up, the official said.

No one has claimed responsibility for the attack, but Turkey’s Interior Minister said today that “all findings show it’s ISIS.”

CIA Director John Brennan said today the attack “bears the hallmarks" of the Islamic State's "depravity.”