Four Turkish soldiers were killed and two others wounded in attacks by Kurdish militants on Saturday, the Turkish defense ministry said. The attack took place in the Tel Rifaat region, where Turkey carried out an operation aimed at driving Islamic State militants and the Kurdish militia from its border with Syria, the ministry said. The Turkish defense ministry also said that the army has since retaliated for the attacks. Turkish Defense Minister Hulusi Akar was later quoted by the state-run Anadolu news agency as saying the military had killed 23 militants as retaliation. A Turkish security official said that the army was carrying out small operations to eliminate threats from the Tel Rifaat region, but that it could launch “a bigger operation” if necessary, Reuters reports. Turkey, one of the main backers of rebel groups fighting against Syria’s President Bashar al-Assad, has conducted patrols with Russia, one of Assad’s main allies, under agreements reached last year.