Turkish special forces units and jets supported by warplanes from the U.S.-led coalition launched an operation in northern Syria on Wednesday to wipe out ISIS militants along the border, officials said.
The operation was launched just hours ahead of a planned visit to Turkey by Vice President Joe Biden. He is the most senior U.S. official to travel to the country since a failed July 15 coup strained ties between the two NATO members and shook confidence in Turkey's ability to step up the fight against ISIS.
The Turkish army began firing artillery rounds into the Syrian border town of Jarabulus at around 4 a.m. (9 p.m. ET) and Turkish and U.S. warplanes pounded ISIS targets with air strikes as part of Wednesday's operation, Turkish military sources said.
It was the first time warplanes from NATO member Turkey have struck in Syria since November, when Turkey downed a Russian jet near the border, and the first significant 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 ISIS 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.
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White and grey plumes of smoke rose from atop the hills of Jarabulus, 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 told Reuters that a ground incursion had yet to start, but a group of Turkish special forces had entered Syria while Turkish and U.S.-led coalition jets hit four ISIS 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 U.S.-led coalition against ISIS," one military source said, adding work to open a passage for ground forces was underway.
Turkey had vowed on Monday to "completely cleanse" ISIS militants from its border region after a suicide bomber suspected of links to the group killed 54 people at a Kurdish wedding in the southeastern city of Gaziantep.
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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 Jarabulus landed in Karkamis and nearby on Tuesday, forcing many residents to flee, a Reuters witness said. Another hit an empty field on Wednesday.
The Syria operation came as Syrian rebels backed by Turkey had said they were in the final stages of preparing an assault from Turkish territory on Jarabulus, aiming to preempt a potential attempt by Syrian Kurdish YPG militia to take it.
Turkey is still in shock after the failed July coup by rogue solders who tried to overthrow President Tayyip Erdogan and the government, killing 240 people and triggering a huge purge of suspected coup supporters in the army and civil service.
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Angered by a perceived lack of Western sympathy over the coup, Turkey has chilled ties with Washington and the European Union while ending a diplomatic spat with Russia and proposing more military cooperation with Moscow in fighting ISIS.
Those growing ties between Ankara and Moscow are worrying Turkey's Western allies.