Smoke billows after an air strike on Jarablus, Syria, 24 August, 2016

Syria Jarablus: Turkish tanks roll into northern Syria, Smoke rises over Jarablus, Syria, 24 August, 2016 Image copyrightAFP Image caption A dozen Turkish tanks have rolled across the Syrian border after heavy Turkish shelling of an area held by so-called Islamic State (IS). Military sources told Turkish media 70 targets in the Jarablus area had been destroyed by artillery and rocket strikes, and 12 by air strikes. Turkish special forces entered Syria earlier as part of the offensive. President Recep Tayyip Erdogan said the operation was aimed against both IS and Kurdish fighters. Turkey shelled Syrian Kurdish forces in the region this week, determined not to let them fill the vacuum if IS leaves, the BBC's Mark Lowen reports from Gaziantep, near the Syrian border. The concern in Ankara is that the Kurds could create an autonomous area close to the border which might foster Kurdish separatism within Turkey itself, our correspondent says. In another development, counter-terror police in Turkey's main city, Istanbul, launched dawn raids targeting IS suspects across the city. US Vice-President Joe Biden arrived in Turkey on Wednesday in the highest-ranking visit by a Western official since the failed coup on 15 July. Bomb survivor haunted by attacks Turkey v Syria's Kurds v Islamic State How dangerous is the instability in Turkey? Islamic State: the full story Map showing control of northern Syria Twin attack The tanks were followed by pick-up trucks believed to be carrying Turkish-backed Syrian rebels from the Free Syrian Army. "At 04:00 [01:00 GMT] our forces began an operation against the Daesh [IS] and PYD [Kurdish Democratic Union Party] terror groups," President Erdogan said in a speech in Ankara. The offensive is aimed at "putting an end" to problems on the border, he said. A Turkish tank heads towards the Syrian border, 24 AugustImage copyrightAFP Image caption At least a dozen tanks were involved A Turkish tank near the Syrian border, 24 AugustImage copyrightEPA Free Syrian Army fighters in pick-up trucks follow Turkish tanks into Syria, 24 AugustImage copyrightEPA Image caption Fighters said to be from the Free Syrian Army followed the tanks in pick-up trucks A coach said to be carrying Syrian rebels stands in Karkamis, near Turkey's Syrian border, 24 AugustImage copyrightEPA Image caption A coach said to be carrying Syrian rebels was spotted by reporters in Karkamis The Turkish town of Karkamis - just across the border from Jarablus - was evacuated as a precaution following earlier IS mortar attacks. Turkey has vowed to "completely cleanse" IS from its border region, blaming the group for a bomb attack on a wedding that killed at least 54 people in Gaziantep on Saturday. This is Turkey's first known ground incursion into Syria since a brief operation to relocate the tomb of Suleyman Shah, a revered Ottoman figure, in February of last year. The air strikes are Turkey's first inside Syria since the downing of a Russian jet in November. Moscow and Ankara only mended ties in June after punitive Russian sanctions. 'A buffer against the Kurds' An unnamed senior US official in Washington told BBC News before the start of the Turkish operation that it was "partly to create a buffer against the possibility of the Kurds moving forward". "We are working with them on that potential operation: our advisers are communicating with them on the Jarablus plan. "We'll give close air support if there's an operation." A Turkish military warning sign, with the closed Karkamis border gate in the backgroundImage copyrightREUTERS Image caption Karakamis - which borders Jarablus - has been evacuated Fighters from the Syrian Kurd YPG militia - the military wing of the PYD - led the battle to drive IS out of the strategic crossroads town of Manbij earlier this month. Turkey views the YPG as an extension of the Kurdistan Workers Party (PKK), a Turkish-Kurdish rebel group fighting for autonomy since the 1980s, but the YPG is backed by the US as one of the most effective forces battling IS. On Tuesday the YPG took control of most of the north-eastern Syrian city of Hassakeh. A truce was reportedly brokered there by Russia after recent clashes between the Kurds and Syrian government forces. President Erdogan said he would press Vice-President Biden for the extradition of US-based cleric Fethullah Gulen, whom he blames for the coup attempt.

Turkish arrest warrant for Gulen Turkish media round on Biden Several pro-government papers accuse Washington of dragging its heels after Turkey's call for the extradition of US-based Turkish cleric Fethullah Gulen. "Gulen's protector" says a headline in Aksam, which notes his "late" visit in the wake of last month's coup attempt. Gunes newspaper says pointedly that "the Turkish government and 79 million Turks are waiting for concrete steps" from him, adding that "Biden will be... asked to behave like an ally". The pro-government Star agrees that Mr Biden will have to explain US support for the "Fetullah Gulen Terrorist Organisation" (FETO). Karar says the visit will open a new chapter in bilateral ties but says Washington must show its support for Turkey. Pro-government daily Milliyet publishes a column by Mr Biden himself where he praises Turks for thwarting the coup attempt. He also says that claims that Gulen's extradition is simply a political matter are "damaging" for bilateral ties. BBC Europe