The claim was made in a statement issued by the Kurdistan Freedom Falcons (TAK), seen as an splinter group of the better-known Kurdistan Workers Party (PKK).
“A revenge squad from TAK carried out simultaneous attacks outside Istanbul Vodafone Arena stadium and Macka park at around 2230 local time (1930 GMT),” according to a TAK statement published on its website.
The militant group said the twin attacks were carried out by two TAK militants, without providing any details about the perpetrators.
Turkish government officials had earlier pointed the finger of blame at the PKK, which has waged a bloody campaign against the Turkish state since 1984.
The carnage prompted a sharp response from President Recep Tayyip Erdogan, who vowed Ankara would “fight the scourge of terrorism right to the end”.
“They should know that they will not get away with it… They will pay a heavier price,” the president said.