Up to 50 Syrian soldiers have been killed in an assault by hundreds of militants in north-western Syria, according to independent sources,However, Russia's defence ministry admitted tht 40 soldiers killed
The ministry, which supports Syria's government, said there were several attacks in which the militants seized two settlements in Idlib province.
Syrian state media said members of a jihadist alliance had set off car bombs and used heavy fire as they targeted positions in the Maarat al-Numan area.
But they did not mention casualties.
A Syrian military source was cited as saying army units were redeployed to the area and eventually repelled the attacks "with high efficiency".
A spokesman for National Liberation Front rebel alliance, Naji Mustafa, said the assault had taken place earlier this week.
Idlib is the last stronghold of the opposition to President Bashar al-Assad and home to three million people, of whom 76% are women and children.
Earlier, At least 40 people were killed in Russian-led air strikes on Tuesday in Aleppo and Idlib in northwest Syria, residents and rescuers said, in a major army assault backed by Iranian militias to clear out rebels in the area.
Among the fatalities were a family of eight, including six children, killed in the rural village of Kfar Taal west of government-controlled Aleppo, as well as nine civilians killed in Maardabseh in the southeast of Idlib province, witnesses told Reuters.
"God take revenge on all tyrants. There is no one else left in my family, they are all gone," Abu Yasser, 71, a relative of the family wiped out in Kfar Taal, said in a voice recording sent to the news agency.
At least 22 other civilians were killed in other strikes by Russian and Syrian government warplanes on rural opposition areas that have been hit hard since the Russian-led military campaign, supplemented by Iranian militias, began in December.
Meanwhile, Syrian state television said on Tuesday that two women and a child were killed in a rocket attack by "terrorists" - its standard term for anti-Assad rebels - on a crowded neighbourhood of Aleppo city.According to the Syrian Observatory for Human Rights, military escalation in Idlib and Aleppo over the past week has caused more than 250 civilian deaths or injuries, and killed more than 200 Syrian and Russian troops as well as rebels.
The UK-based group said that between 15 and 22 January, its activists had documented nearly 4,000 air and ground strikes targeting the countryside of both Idlib and Aleppo.
Russian forces bombarded towns including Kafr Nouran and Kafr Naha, leading to multiple civilian deaths, the group said.
The aerial bombings, in which Moscow has also deployed special forces on the ground to push deeper into rebel-held territory, has left dozens of towns in ruins and knocked down hospitals and schools, rescuers and aid agencies say.
Moscow and Damascus deny accusations of indiscriminate bombing of civilians, saying they are fighting the militant group Hayat Tahrir al-Sham, which controls most of Idlib and who they say have stepped up their attacks on civilians in Aleppo city.
