Thirty-eight Islamic State militants were killed in northern Syria over the last 24 hours, the Turkish military said on Sunday, marking an escalation of conflict in the area where Syrian rebels, backed by Turkey, are fighting the jihadists. Supported by Turkish tanks and air strikes, rebels have been pushing towards the Islamic State (IS) stronghold of Dabiq in an operation launched in late August.Fourteen of the IS fighters were killed as they attempted to enter the rebel-controlled villages of Akhtarin and Turkmen Bareh, three kilometres (two miles) east of Dabiq, the Turkish army said in a statement.The British-based Syrian Observatory for Human Rights said on Saturday that IS fighters had captured those villages in a counter attack near the Turkish border, but the Turkish military statement contradicted this account.Another 17 Islamic State fighters were killed in air strikes by U.S.-led coalition warplanes in the same areas, the military said in its daily round-up on the operation, dubbed "Euphrates Shield".Turkish warplanes later launched their own air strikes against IS targets in northern Syria on Sunday morning, killing seven militants and destroying five buildings which they were using, the army said in a subsequent statement.The military also said two Syrian rebels had been killed and 19 wounded in the latest fighting against IS. The operation has also targeted a Kurdish militia whose presence along its border Turkey sees as a threat. ..