"Our fighter planes ... Along with planes from the coalition yesterday evening began joint operations against (IS) targets which pose a threat to the security of our country," it said in a statement.
US Defense Secretary Ashton Carter last week called on Turkey to play a full part in the US-led air campaign against the Islamic State group and take better control of its border with Syria.
He said Ankara had agreed in principle to join the anti-IS coalition but should add its own warplanes to the "air tasking order," the military structure coordinating strikes.
"Their leadership has indicated that this needs to be done. It's overdue, because it's a year into the campaign, but they're indicating some considerable effort now."
Turkey agreed last month to step up its involvement in the war raging across its southern border in Syria and to allow US planes to launch strikes from a Turkish base.
But its involvement in the battle against the IS group had been limited and it appeared to be concentrating on its recently revived war with Kurdish separatist militants.