Turkish special forces units and jets supported by warplanes from the US-led coalition have launched an operation in northern Syria to wipe out Islamic State militants along the border with Turkey.
The Turkish army began firing artillery rounds into the Syrian border town of Jarablus on Wednesday (AEST) and Turkish and US warplanes pounded Islamic State targets with airstrikes as part of the operation, Turkish military sources said.
It was the first time warplanes from NATO member Turkey have struck in Syria since November, when Turkey shot down a Russian jet near the border, and the first known incursion by Turkish special forces since a brief operation to relocate the tomb of Suleyman Shah, a revered Ottoman figure, in February 2015.
Turkey and the United States hope that by sweeping IS from the border, they can deprive it of a smuggling route which long saw its ranks swollen with foreign fighters and its coffers boosted by illicit trade.
White and grey plumes of smoke rose from atop the hills of Jarablus, visible from the Turkish town of Karkamis across the border. The boom of artillery fire was audible as tanks opened fire from just inside Turkish territory.
Turkish military sources said a ground incursion had yet to start, but a group of Turkish special forces had entered Syria while Turkish and US-led coalition jets hit four Islamic State targets and Turkish artillery struck more than 60 targets. Tanks were being positioned to secure the border, they said.
"The aim of the operation is to ensure border security and Syria's territorial integrity while supporting the US-led coalition against Islamic State," one military source said, adding work to open a passage for ground forces was underway.
US Vice President Joe Biden is due in Turkey later on Wednesday, the most senior US official to visit since a failed July 15 coup shook confidence in the ability of the NATO member to step up the fight against Islamic State.
Turkey had vowed on Monday to "completely cleanse" IS militants from its border region after a suicide bomber suspected of links to the group killed 54 people at a Kurdish wedding in southeastern city of Gaziantep.
Counter-terrorism police launched dawn raids targeting Islamic State members across Istanbul on Wednesday, the Dogan news agency said.
Turkey is also concerned about the growing influence of Syrian Kurdish militant groups along its border, where they have captured large areas of territory since the start of the Syrian war in 2011. Ankara sees them as tied to the Kurdish militants fighting an insurgency in Turkey.
At least nine mortar shells from Jarablus had landed into Turkish border town of Karkamis and nearby on Tuesday, forcing many residents to flee the town, a Reuters witness said.
The Syria operation also came as Syrian rebels backed by Turkey had said they were in the final stages of preparing an assault from Turkish territory on Jarablus, aiming to pre-empt a potential attempt by Syrian Kurdish YPG militia to take it.
