Ankara (AFP) – A Russian-Turkish deal for a buffer zone around Syria’s last rebel stronghold was a “major step” that has “frozen” the country’s devastating seven-year war, a US envoy said Wednesday.

James Jeffrey, Washington’s special representative on Syria, spoke a day after regime ally Russia and rebel backer Turkey said their agreement creating a demilitarised zone skirting Idlib province was on course despite jihadists missing a Monday deadline to withdraw.

The deal “is a major step because what it’s done is it has frozen the conflict not only there, but the conflict is also frozen essentially everywhere else,” Jeffrey told journalists in the Turkish capital Ankara.

The agreement, reached last month, was seen as forestalling a devastating regime assault on the area, which hosts around three million people.

It gave opposition and jihadist fighters until October 10 to clear the buffer zone of any heavy weapons.

But Monday’s second deadline for the withdrawal of “radical” fighters — taken to mean jihadist heavyweight Hayat Tahrir al-Sham (HTS) and other hardliners — was seen as the accord’s real test.

On Tuesday, more than 24 hours after the deadline, the Syrian Observatory for Human Rights monitor said there were “no signs” HTS fighters were evacuating.

But Jeffrey said Wednesday that “by and large the Russians seem to be willing to continue this”.

Jeffrey said US officials and their Turkish counterparts were now discussing “revitalising the political process now that you have essentially a de facto, or at least temporary ceasefire throughout the country” apart from minor battles and a US-led campaign against Islamic State group holdouts.