According to the Syrian Observatory for Human Rights, Syrian military forces advanced toward Kabani hill, in the coastal Latakia Province. The hill is held by a rebel coalition dominated by al-Qaeda’s Nusra Front, and overlooks their town of Jisr al-Shughour.
Rebels involved in the defense of the hill implied the move was a violation of the ceasefire, though the ceasefire explicitly excludes Nusra and ISIS, and allows everyone to continue attacking them.
Jisr al-Shughour is in Idlib Province, which is dominated more or less entirely by a Nusra-led coalition, and the town closest to Latakia Province, meaning it is likely to be the first target of a Syrian offensive into Idlib.
Nusra’s close ties with rebels groups the US considers “moderate” was seen as a big obstacle to the ceasefire in the first place, as Nusra has a presence in a lot of those rebels’ territory too, meaning attacks targeting them could span territory that was ideally to be part of the ceasefire.
So far, however, that’s largely not happened, and Syria has launched limited offensives, seemingly targeting only that territory which was dominated by Nusra forces, leaving hope that the truce can hold through peace talks scheduled for next week.