Turkish tanks cross border into Syria to clear town of Islamic State militants, military sources, says Reuters.

The aim of the operation, codenamed "Euphrates Shield" is to secure territory along its border with Syria from the ISIS threat, officials told Turkey's semi-official Anadolu agency.

Turkish artillery units and warplanes belonging to the US-led coalition pounded the ISIS-held Syrian town of Jarablus in the early hours of Wednesday.

Turkish tanks and special forces units are also operating along the border, CNN affiliate CNN Turk reported.

Jarablus lies along the west bank of the Euphrates River, less than a kilometer from Turkey. It's the last major town held by ISIS on the Syrian-Turkish border.

Turkey has been hitting targets inside Syria for the past three days, following a mortar attack on residential areas in Karkamis, a town on the Turkish side of the border.