Russia is not opposed to launching a full-scale assault on militant-held Idlib alongside Syrian government forces but said that the operation was unpractical for now, President Vladimir Putin said on Saturday.
The news came as Hayat Tahrir Al Sham and another hardline group killed at least 22 Syrian government troops and militiamen in the northern province of Aleppo early on Saturday, a war monitor said.
Russia, one of the Syrian government’s staunchest allies, and Turkey brokered a deal in September to create a demilitarised zone in the north-west Idlib region that would be free of all heavy weapons and hardline fighters. However, the deal has never been implemented.
The deal helped to avert a government assault on the region, the last major bastion of opponents of President Bashar Al Assad. It is home to three million people, and many of the civilians fled regime offensives in other areas of the country.
The latest militant raid in the southern and south-western countryside of Aleppo province began shortly after midnight and triggered clashes that continued until dawn, the British-based Syrian Observatory for Human Rights said.
As well as more than 20 regime forces killed, the Al Qaeda affiliate and its ally Hurras Al Deen – which is still affiliated to the global jihadist network – wounded 30 others.
The fighting subsided after Russian aircraft struck the militant positions in the area, prompting the fighters to pull back. Eight militants were killed.
Moscow has complained about escalating violence in the area and said that militants who used to belong to Hayat Tahrir Al Sham are in control of large areas of territory.
After the Turkish and Russian-backed agreement, the hardline group used the breathing room to launch an offensive to take over much of the province and consolidate control.
Speaking in Beijing, Mr Putin said that Moscow and Damascus would continue what he called the fight against terrorism and that any militants who tried to break out of Idlib, something he said happened from time to time, were bombed.
But Mr Putin said the presence of civilians in parts of Idlib where militants were also active meant the time was not yet ripe for full-scale military operations.
"I don't rule it [a full-scale assault] out, but right now we and our Syrian friends consider that to be inadvisable given this humanitarian element," Mr Putin said. Despite his assurances that civilian losses should be minimised, scores of non-combatants have been killed in recent months owing to Russian airstrikes as well as regime shelling.
Russian aircraft carried out strikes in neighbouring Hama province early on Saturday, killing five civilians, the observatory said.
On Friday, Russian strikes killed 10 civilians in Idlib province, the hub of territory held by Hayat Tahrir Al Sham in north-western Syria.
Moscow is keen to help the Assad regime retake all territory, including eventually Idlib province, but Turkish President Recep Tayyip Erdogan has argued against a Russian-backed offensive in a region that borders his own country.
Ankara is concerned about potential refugee flows from Idlib in the event of a military operation, and wants to retain its influence there.
Late last week, Turkey, Russia and Iran – which has backed Damascus since early in the conflict, met in Kazakhstan, where they expressed concern over the growing power of Hayat Tahrir Al Sham in Idlib and parts of adjacent provinces. They are determined to co-operate and eliminate the hardline militant group.
The civil war in Syria has killed more than 370,000 people and displaced millions since it began with the bloody repression of anti-government protests in 2011.