Blasts in the eastern Syrian city of Raqqa on Wednesday were caused by an ISIS mine and not a wave of suicide bombs as previously claimed, a US-backed force said on Wednesday. The head of the Syrian Democratic Force's (SDF) media office Mustafa Bali told journalists in an online message that earlier information it provided about suicide bombings in the city, captured from ISIS in 2017, was wrong. ISIS has left a trail of booby traps in the cities that it captured across Iraq and Syria and had to flee in recent years. The guerrilla warfare tactic has made it increasingly difficult for coalition-backed forces to clear population centres of dangerous explosives. The SDF drove ISIS from Raqqa in 2017 but the fierce military campaign there, including intensive air strikes from a US-led coalition, left much of the city in ruins. ISIS fighters are still holding out in a remote area of the Syrian desert and security officials say others have gone under ground in Iraqi cities. Spearheaded by the Kurdish YPG militia, the SDF's hold over northeastern Syria, including much of the border with Turkey, alarms Ankara which regards it as a terrorist group. On Tuesday, the SDF was battling ISIS in eastern Syria 10 days after declaring victory over the extremists, Mr Bali said. He said they are rooting out groups of militants who were hiding in caves in and near the village of Baghouz. He added that SDF experts are still removing mines and booby-traps in areas liberated in recent weeks. The SDF declared military victory over ISIS on March 23 after liberating what it said was the last pocket of territory held by the militants. The victory marked the end of the brutal self-styled caliphate the group carved out in large parts of Iraq and Syria in 2014. The nearly five-year war left a swath of destruction across both countries and ended in Baghouz, a tiny village near the Iraqi border where the cornered militants made their last stand, under a grueling siege for weeks. The Britain-based Syrian Observatory for Human Rights said the US-led coalition is still conducting air strikes against ISIS. It says senior ISIS commanders and prisoners held by the extremists are believed to be in the caves on the east bank of the Euphrates River.