Flowers are placed in front of a police barrier near the entrance of Reina nightclub in Istanbul, Turkey ( January 1, 2017)
VON PRESS Middle East: Security forces have released pictures of the suspect who went on the rampage at Reina nightclub on New Year's night, spraying some 120 bullets at terrified guests before slipping away into the night.
Until now,16 people have been held over the attack, including two foreigners detained by Turkish police at Istanbul's main airport. But the killer remains on the run.
Most of the dead are from foreign countries, mainly from Arab countries, with coffins repatriated overnight to their countries.
The Islamic State (ISIS) group on Monday claimed the massacre, the first time it has taken responsibility for a major attack in Turkey.
The suspect -- who has not been named but was reportedly from Central Asia -- was staying in a rented flat in Konya before moving to Istanbul to carry out the attack, press reports said.
The local media reported those detained included a woman suspected of being his wife with whom he had stayed in Konya along with two children.
They added police have made progress in the investigation after speaking to the taxi driver who drove the attacker to the club and tracing calls he had made on the driver's mobile phone.
Hurriyet daily has uttered the attacker showed signs of being well trained in the use of arms and had fought in Syria for ISIS terror group.
Hurriyet's well-connected columnist Abdulkadir Selvi said he had been trained in street fighting in residential areas in Syria and used these techniques in the attack, shooting from the hip rather than as a sniper.
The suspect had been "specially selected" to carry out the shooting, he said. According to Hurriyet, just 28 bullets failed to hit a target.
"This specially-trained terrorist has still not been detained and is still wandering dangerously amongst us," he wrote.
He added an ISIS terror attack was also planned in Ankara on New Year's Eve but that it had been foiled after eight ISIS suspects were arrested in the capital. There were no further details.
Police meanwhile released the first clear images of the attacker, including one taken by security cameras on the night of the attack.
Turkish media released a 'selfie video' of the suspected Reina nightclub attacker in Istanbul
And a chilling video of the suspect taken near Taksim Square in central Istanbul was also released, showing him recording himself with a selfie stick and smiling faintly into the camera.
Reports said that the attacker could be from Kyrgyzstan or Uzbekistan. In Bishkek, the national Security Council said it was checking any possible involvement of a Kyrgyz citizen.
In a statement circulated on social media, ISIS terror group said one of its "soldiers" had carried out the carnage, accusing Turkey -- a majority-Muslim country -- of being a servant of Christians and saying the shooting was a response to Ankara's military action against terrorists in Syria.
Turkish troops are pressing a four-month incursion to oust ISIS terrorists the border area while Ankara is also pushing a ceasefire plan with Russia as a basis for peace talks to end the civil war.
After a cabinet meeting in Ankara chaired by President Recep Tayyip Erdogan, the government vowed that the operation in Syria would continue with "determination".
37 foreigners who died -- most of them from Arab countries -- had come to the club to celebrate a special night in style.