With a deadline for establishing a demilitarised zone around Syria's Idlib inching closer, confusion and apprehension is rife among Turkish-backed rebels who fear it will cost them their last stronghold. Two weeks ago, regime ally Moscow agreed with Ankara to create a buffer area ringing Idlib in a bid to avert a massive government blitz on the northwestern opposition bastion. Most rebels cautiously welcomed the deal, but the last two days have seen many factions raise objections over several of the accord's key points and demand clarifications from Turkey. Those concerns came to a head at the weekend, with a major Turkish-backed rebel alliance denying reports it had begun implementing the agreement and rejecting any future Russian presence in the planned zone. "There's still disagreement and debate over the explanation of some points," said Naji Mustafa, spokesman for the National Liberation Front, which welcomed the agreement last month. The accord was reached on September 17 by Russian President Vladimir Putin and Turkish counterpart Recep Tayyip Erdogan in the Russian resort town of Sochi. Announcing the deal, Putin said the 15-20 kilometre buffer would fall along the "contact line" between rebel and regime forces, without specifying a geographic location. All factions in the demilitarised zone must withdraw heavy weapons by October 10, and radical groups must leave by October 15. Turkish troops and Russian military police would then monitor the zone, he said. - 'Still coordinating' - But questions remain over the finer details, said Sam Heller, analyst at the International Crisis Group. "Broadly, the deal that was reached in Sochi is itself unclear and doesn't include many practical details," Heller told AFP. "That's why there has been no clear vision for the Syrian opposition on its implementation," he said. "Technical talks" were held in recent days between Moscow and Ankara, and Turkish officials are meeting with rebels to clarify the accord's execution. "We are still coordinating with the Turkish guarantor on following the agreement and ways to implement it," said Sayf al-Raad, spokesman for Faylaq al-Sham, a member of the NLF. The rebels' lasting apprehension seems to stem from two points. First, they worry the zone would be carved exclusively out of rebel territory, with the regime losing no ground. That prompted Jaish al-Izza, a formerly US-backed group, to reject the accord at the weekend. "We are against this deal, which eats into liberated (rebel-held) areas and bails out Bashar al-Assad," Jaysh al-Izza chief Jamil al-Saleh told AFP. He feared "the buffer zone would only be from our side," demanding it be created "evenly" from regime and rebel zones. The second concern is that a Russian military presence would inevitably pave the way for regime troops to enter. That, the NLF told Ankara on Sunday, would be a red line. "We discussed the issue, and the NLF took a clear position rejecting this matter," rebel spokesman Mustafa said, adding that Turkey "pledged that it would not happen". - 'Not consulted' - A Syrian source close to rebels blamed the muddied waters on poor coordination. "The difficulties arise from the fact that the Syrian rebel groups are not closely consulted when the Turkish side seals agreements with the Russians," the source told AFP. Heller said rebel concerns may be legitimate. "It was clear from the original Russian-Turkish agreement, published after Sochi, that the demilitarisation zone would be within opposition territory only," said Heller. And as the regime's main global ally, Russia has an interest in chipping away at rebel territory. "It's unthinkable for Russia to sign a deal that includes a gap in the sovereignty and control of Syria's government over Syrian territory," said Heller. All patrols could ultimately get struck off "given the presence of some factions and jihadist groups that may target any foreign presence, even Turkish," he said. The confusion has already played out on the ground, with the NLF and Faylaq al-Sham denying reports on Sunday that they had pulled heavy weapons from the planned zone. Most of the territory where the zone would be established is controlled by either hardline jihadists or by Hayat Tahrir al-Sham, an alliance led by former Al-Qaeda members and widely considered the most powerful force in Idlib. The rest is held by the NLF and other rebels. HTS has yet to announce its position on the deal but has shown no sign it is moving out either fighters or heavy weapons. Al-Qaeda loyalists Hurras al-Deen, which have a presence in the zone, rejected the deal last week.