A jihadi assault gained ground on Tuesday against Turkish-backed rebels in northwest Syria, edging closer to front-lines with government forces, a rebel official and a war monitor said.
The advance raises questions about the fate of September's demilitarization deal between Turkey and Russia, which staved off a Syrian army offensive against the Idlib region.
Hayat Tahrir al Sham (HTS), spearheaded by al-Qaida's former Syrian affiliate, is expanding its grip over the insurgent enclave, which includes Idlib province and adjacent bits of Aleppo, Hama and Latakia provinces.