Syrian rebels have shot down a regime helicopter in an escalation of violence in Idlib province that threatens to suck Turkey into full-blown war with President Assad. It was downed in Nairab, west of Saraqeb, by fighters from Hayat Tahrir al-Sham (HTS), the successor of al-Qaeda in Syria. It released images of the burning Mil Mi-17 crashing to the ground near badly damaged apartment blocks. The group also claimed to have retaken ground from the regime in the same area after heavy clashes and airstrikes. President Assad’s forces are pushing into Idlib, the last rebel-held province, from the south and are using helicopters to drop barrel bombs on residential areas. The heaviest fighting is around Atareb, northeast of Idlib city.