Damascus, Jan 12 : Syria began the new year by witnessing a "significant escalation" of attacks by the Islamic State (IS) terrorist group, a war monitor said. In a fresh report, the Syrian Observatory for Human Rights said of the 26 attacks carried out by the IS, 11 targeted the strongholds of the Syrian Democratic Forces (SDF), leading to the deaths of four SDF fighters and the injuries of six others, reports Xinhua news agency. Moreover, the terrorist group carried out 15 additional attacks and ambushes against Syrian military personnel in various regions, including the west of the Euphrates, the desert areas of Deir al-Zour, Raqqa, and Homs provinces. The attacks resulted in the deaths of 46 Syrian soldiers and pro-government fighters, including four Iran-backed fighters, and the injuries of 47 others, said the Britain-based watchdog group, adding that a civilian was also killed during the attacks. On Tuesday, an IS-claimed attack killed at least 14 soldiers aboard a military bus in the desert near the ancient city of Palmyra, according to the war-monitor, in the second such attack this year. Syria's Defence Ministry confirmed the attack but gave a lower death toll of eight. Last week, IS killed nine Syrian government soldiers and militiamen in an attack on military posts in the eastern desert, according to the Britain-based Observatory. In June 2014, the IS had proclaimed a "caliphate" across Syria and Iraq and launched a reign of terror. It was defeated territorially in Syria in 2019 but the spike in recent attacks is raising renewed concerns about the resurgence of the terrorist organisation within Syria. /IANS