 Complete the following phrase:  On 19 September, members of Tahrir al-Sham, alongside the TIP and militants aligned to the FSA, launched an offensive on pro-government and Russian Armed Forces positions overseeing the process of the de-escalation of the zone in the province of Idlib following an agreement with Turkey and Iran in negotiations in Astana in May 2017. Reports of the ensuing fighting were contradictory. The rebels initially captured four villages, but after back-and-forth fighting during which the villages changed hands several times, government forces recaptured all of the villages by 22 September. Russia stated it had killed 850 rebel fighters by 21 September. In contrast, SOHR reported that 66 rebels and 38 soldiers were killed during the offensive, as well as more than 40 civilians over two days in nearly 500 air-strikes on about 40 towns and villages in retaliation for the rebel offensive. There were also rebel claims of government and Russian airstrikes on civilian targets in Idlib, including medical facilities. The Russian Air Force and Russian Navy conducted air and cruise missile strikes against HTS targets, reportedly including a large military camp. The US State Department accused Syria and Russia, besides bombing civilian targets, of also targeting medical facilities. One of the three allegedly bombed hospitals was the al-Rahma clinic in Khan Shaykhun, which treated victims of the 