In eastern Syria, meanwhile, government forces reportedly entered a town that's one of the biggest strongholds of the Islamic State group.
According to the Britain-based Syrian Observatory for Human Rights, Syrian forces and allied militiamen entered western parts of Mayadeen, including the town's wheat silos compound and the sheep market.
The government-controlled Syrian Central Military Media earlier said that troops were marching south from Deir el-Zour toward Mayadeen, under the cover of airstrikes.
If the report proves true and Syrian troops indeed entered Mayadeen, it would mark another blow for the extremist group, which has lost wide areas of Iraq and Syria in its self-declared caliphate over the past year.
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Airstrikes on Mayadeen and nearby areas over the past days have killed and wounded scores of people, including 15 civilians -- women and children among them -- who were killed when a missile slammed into a government-held neighborhood in the city of Deir el-Zour yesterday evening.
The attack on the village of Abu Dali in central Hama province was led by al-Qaida-linked Hay'at Tahrir al Sham Arabic for Levant Liberation Committee and also known as HTS. It came two weeks after insurgents attacked a nearby area where three Russian soldiers were wounded.
The al-Qaida-linked group subsequently denied al-Golani was hurt, insisting he is in excellent health and going about his duties as usual. The group's fighters have been gaining more influence in the northwestern province of Idlib and northern parts of Hama, where they have launched attacks on rival militant groups, as well as areas controlled by the government.
Abu Dali had been spared much of the violence and had functioned as a local business hub between rebel-run areas and those under President Bashar Assad's forces.
Violence in eastern Syria has escalated significantly in recent weeks as Syrian troops with the help of Russian air cover have been closing in on Mayadeen.
The DeirEzzor 24 monitoring group said the missile in yesterday evening airstrike that killed 15 hit near a school in the Qusour neighborhood. Three children and three women were among those killed, the group said today, blaming IS for the attack. The school and a nearby residential building were destroyed.
Syrian troops broke a nearly three-year siege on parts of Deir el-Zour last month and are now fighting to liberate the remaining parts of the city from IS.
In Russia, the military said one of its helicopters had made an emergency landing in Syria but that its crew was unhurt.
According to the Defence Ministry, the Mi-28 helicopter gunship landed in Hama province today due to a technical malfunction. The two crewmen were not injured and were flown back to base. The ministry said the helicopter was not fired upon.
Also today, the Russian military accused the United States of turning a blind eye and effectively providing cover to IS operations in an area in Syria that is under US control.
The Defence Ministry's spokesman, Maj Gen Igor Konashenkov, said IS militants have used the area around the town of Tanf near Syria's border with Jordan -- where US military instructors are also stationed to launch attacks -- against the Syrian army.
The area has become a "black hole," posing a threat to Syrian army's offensive against the IS in eastern Der el-Zour province, he added.