Jihadists and their allies cut a major highway linking the main cities of Damascus and Aleppo on Thursday after launching an offensive against government forces in Syria's northwest, a war monitor said.
"Hayat Tahrir al-Sham (HTS) and allied factions cut off the Damascus-Aleppo international M5 highway... in addition to controlling the junction between the M4 and M5 highways," said the Syrian Observatory for Human Rights.
The government and its allies had responded to the large-scale attack with airstrikes and shelling to ward off the insurgent advances, activists said.
The violence has displaced thousands of families, and forced aid groups to suspend some of their services. Volunteers with the Syrian Civil Defense, known as the White Helmets, said at least 18 people, including three children and two women, were killed in two different villages in western Aleppo following airstrikes. The Syrian Observatory for Human Rights, a war monitor, said the airstrikes were from Russian warplanes.
Syria's armed forces said Thursday the offensive was led by Hayat Tahrir al-Sham, or HTS, which controls much of northwest Syria and is a violation of a de-escalation agreement. It said the attacks are ongoing and have targeted a number of villages and military bases.
Turkey, which backs Syrian opposition factions, and Russia and Iran, which have backed government forces, reached an agreement in late 2019 that effectively froze the line of the conflict and prevented government advances in Idlib province, which has been the last stronghold for a mix of radical groups and Turkey-backed Syrian forces.
"Our forces are confronting the terrorist organizations with different power and in collaboration with friendly forces to ensure the situation returns to how it was," the army statement said.
Opposition factions launched the offensive early Wednesday and claimed in a series of statements on social media that they have wrestled control of over 15 villages from government forces in northwestern Aleppo, capturing a military base and hardware, and taking a number of soldiers hostage.