ISTANBUL (Reuters) - Thirty one Islamic State in Iraq and Syria (ISIS) militants have been killed in clashes and United States-led coalition air strikes in northern Syria over the last 24 hours, the Turkish military said on Sunday (Oct 9), marking an escalation in violence in the area.

Syrian rebels, backed by Turkish tanks and air strikes, have been pushing towards the ISIS stronghold of Dabiq, a village with symbolic importance to the militants, in an operation launched in late August.

Fourteen of the ISIS fighters were killed as they attempted to enter the rebel-controlled villages of Akhtarin and Turkmen Bareh, 3km 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.

Another 17 ISIS fighters were killed in air strikes by coalition warplanes in the same areas, the military said in its daily round-up on the operation, dubbed "Euphrates Shield".

It said two Syrian rebels had been killed and 19 wounded in the latest fighting against ISIS.

The operation has also targeted a Kurdish militia whose presence along its border Turkey sees as a threat.