Turkish police are still struggling to locate the gunman who killed 39 people in a nightclub in Istanbul on January 1, but more information about the assailant is emerging.

The suspect is believed to be from East Turkestan and he came to Turkey with his family in November last year, according to local media.

Police launched raids in Istanbul last night, arresting at least 12 people in connection with the attack.

Meanwhile, a video allegedly showing the suspect recording a selfie in Istanbul’s Taksim Square has been circulating on social media since last night. But his identity remains unknown.

Islamic State has claimed the responsibility for the attack. “The apostate Turkish government should know that the blood of Muslims shed with airplanes and artillery fire will, with God's permission, ignite a fire in their own land,” the jihadi group said in a statement, Reuters reported. The statement suggested that it was a revenge attack for Turkey’s military operations in Syria.

Turkey launched Operation Euphrates Shield in August in northern Syria to clear its borders of Islamic State forces. The military says it has killed hundreds of militants and a number of Islamic State targets there since.

Turkey’s military operation in Syria has stirred terror groups and those behind them into action, the government spokesman Numan Kurtulmus said on January 2. Operation Euphrates Shield will continue until all terror threats to Turkey are eliminated, he added.

Meanwhile, Prime Minister Binali Yildirim is planning to visit Iraq later this week to discuss cooperation against terrorism. Turkey sent troops to northern Iraq to train local forces against Islamic State. But the government in Baghdad has criticised Ankara’s move, demanding the withdrawal of Turkish troops.