Three accomplices in the Daesh suicide bombing that killed 12 German citizens in Istanbul's Sultanahmet in 2016 were sentenced to aggravated life imprisonment on Wednesday.

Tried at Istanbul's 14th High Criminal Court, the prosecutor had previously sought 13 life sentences for the three, one count for disrupting the constitutional order and 12 counts for each killed victim of the attack. The trio was also charged with attempted murder for injuring 16 people in the attack and possessing dangerous materials.

The defendants given super-aggravated life sentences are Atala El Hasan El Mayyuf, Fevzi Muhammed Ali and Turkish national Halil Derviş. They were separately been handed 329 years in prison.

Meanwhile an Iraqi national was convicted of membership in Daesh, but was released due to the length of time he was held in pre-trial detention.

The prosecutor demanded one defendant, namely Abdurrahman Faiz Rashid, to receive a prison sentence up to 15 years for "being a member of the Daesh terror group," while requested the remaining 22 suspects be acquitted.

On Jan. 12, 2016, Syrian national Nabil Fadli blew himself up in Istanbul's Sultanahmet district killing 12 German citizens and injuring 16 others.

In court proceedings, it was stated that Mayyuf, Ali and Derviş organized the terrorist act, ordering Nabil Fadil to detonate a bomb attached to his body.

An indictment into the attack had said that the four men—three Syrians and one Iraqi—helped smuggle the bomb and the suicide bombers into Turkey across the Syrian border one month ahead of the attack.

Turkish security forces have been involved in a long-running campaign to thwart Daesh attacks. More than 300 people have lost their lives in Daesh-claimed attacks in Turkey, where the terrorist group has targeted civilians in suicide bombings, and rocket-and-gun attacks.

The country's efforts against Daesh made it a primary target for the terrorist group, which has carried out numerous gun and bomb attacks targeting security forces and civilians.

This includes the country's deadliest terrorist attack, which killed 102 people and wounded 400 others in a twin suicide bombing at a peace rally in Ankara on Oct. 10, 2015.