Syrian insurgents on Sunday denied pulling any heavy arms out of a major opposition stronghold in the north, as the deadline to implement a demilitarization agreement approaches, agencies reported.

Assad regime ally Russia and rebel backer Turkey agreed earlier in September to establish a buffer zone around the opposition bastion of Idlib that would be free of both jihadists and heavy arms.

The agreement has so far averted a massive offensive by Syrian President Bashar al-Assad’s government, but the implementation of it is expected to be challenging.

The National Liberation Front (NLF), a pro-Turkey rebel coalition, welcomed the deal but said Sunday it had not yet removed any heavy arms from the planned zone.

“There have been no withdrawals of heavy weapons from any area or any front,”  NLF spokesman Naji Mustafa told AFP.  “This report is denied, completely denied.”