Turkey captain Arda Turan has led condolences from the world of football after Istanbul was hit by a terror attack on New Year's Eve.
At least 39 people were killed when a gunman opened fire on a nightclub in the Ortakoy region of the city.
Istanbul was also affected by a bomb attack outside of Besiktas' stadium in December, which killed 44 people.
Arda posted on Twitter: "Yes, we are suffering, but we will come together, stand as one and we will not let terrorism prevail. My condolences to you, my Turkey."
Besiktas added in a statement: "Terrorists who previously attacked our soldiers and police forces, have committed a vulgar attack, this time on civilians. We have complete faith in our fight against terror as a nation united."
Istanbul's other major clubs Galatasaray and Fenerbahce also offered statements of condolence.
Fener paid tribute to "the people who lost their lives as a result of this horrific terror act", while Gala said: "People whose only desire was to have a good time were murdered by a vile and inhumane act of terror."
Sefa Boydas, a footballer with lower-league Turkish club Beylerbeyispor was at the club during the attack.
He is quoted by AFP: "Just as we were settling down, by the door there was a lot of dust and smoke.
"Gunshots rang out. When those sounds were heard, many girls fainted. My girlfriend also fainted and I carried her on my back.
"They say 35 to 40 died but it's probably more because when I was walking, people were walking on top of people."