Turkey on Tuesday pounded Daesh (the so-called IS) militants in Syria with new artillery strikes as expectations grew of a major Ankara-backed offensive against the militants after a deadly suicide bombing on its soil. With tensions flaring on the Turkey-Syria border following the bombing in the nearby city of Gaziantep that left 54 people dead, Turkish howitzers on Monday hit militant and Kurdish rebel targets across the frontier. Turkey has been shaken by one of the bloodiest years in its modern history, with a string of attacks by Daesh fighters and Kurdish militants and the botched July 15 coup. In new fighting on Tuesday, two mortar rounds fired from a Daesh-controlled area in Syria hit the southeastern Turkish town of Karkamis, Turkish television reported. Turkish artillery responded by hitting four Daesh positions around the jihadist-controlled Syrian town of Jarablus with around 60 shells, it said. The shelling came after as activists said hundreds of Ankara-backed rebels were preparing an offensive against the Daesh group to seize control of Jarablus. But this could potentially put them on a collision course with the militia of the Kurdish Democratic Union Party (PYD) which Ankara vehemently opposes and also has its eyes on Jarablus after seizing the strategic Manbij area in northern Syria from Daesh. Rami Abdul Rahman, the head of the Syrian Observatory for Human Rights, said the "Turkish shelling in Syria aimed to prevent the advance of troops backed by Kurds from Manbij toward Jarablus". Abdulkadir Selvi, a well-connected columnist for the Hurriyet daily, said the Turkey-backed offensive "could begin at any moment". The plan has not been confirmed by the Turkish authorities but Foreign Minister Mevlut Cavusoglu said Monday that the border area had to be "totally cleansed" of militants. The movements have come at a critical juncture for Turkey in Syria's five-and-a-half-year war, with signs growing it is on the verge of a landmark policy shift. Ankara has always called for the ouster of President Bashar Al-Assad as the key to ending the conflict, putting Turkey at odds with his main supporters Iran and Russia. However Prime Minister Binali Yildirim at the weekend for the first time acknowledged that Assad was one of the "actors" in Syria and may need to stay on as part of a transition. On Monday, he urged world powers including Iran, Russia and the United States to join together to rapidly open a "new page" in the Syria crisis. "It is essential that all the parties come together to stop the bloodshed in Syria," said Yildirim, whose naming as prime minister earlier this year was seen as heralding a less confrontational Turkish foreign policy. But he also warned it was "unacceptable" for Kurds to seek to establish any kind of separate entity in northern Syria. Turkey regards PYD as a terror group, although Washington, Ankara's ally in the fight against IS, sees its militias — the powerful Kurdish People's Protection Units (YPG) — as having an important role in the fight. US Vice President Joe Biden is due to visit Ankara Wednesday for crucial talks with key leaders and Syria is set to be a crucial issue.