BEIRUT (AP) -- Insurgents led by an al-Qaida-linked group in Syria launched a wide offensive on Tuesday against Syrian pro-government troops, moving south of their stronghold in the western province of Idlib.
The push, believed to involve thousands of fighters, was met with intensive aerial bombing and a shelling campaign by the government that hit, among other targets, four medical centers in Idlib. At least one civilian was killed and two hospitals were rendered non-operational, activists said.
The offensive comes days after Russia and Iran, supporters of Syria's President Bashar Assad, and Turkey announced they were working on a plan to establish and observe a "de-escalation zone" in Idlib - the last of four such areas. The zones already established have greatly reduced violence around Syria.
The "de-escalation zones" near Damascus, central Homs and southern Syria have also freed the Syrian troops and allied militias to push their offensive against Islamic State militants in the eastern Deir el-Zour province and south of Hama.
Tuesday's developments come as pro-government troops seek to consolidate their hold on the city of Deir el-Zour in the east, where they are battling remaining pockets of IS militants. The Syrian forces also crossed to the eastern bank of the Euphrates, bringing them on the same side of the river as the U.S-backed Syrian fighters who are waging a separate offensive against IS.
The Syrian government-affiliated Central Military Media outlet said troops and allied militias pushed back against the offensive that started Tuesday in northeastern rural Hama province, on the border with Idlib, killing a number of insurgents. The Media center said intensive air raids targeted the insurgents in Atshan, Skeik, Morek and Kfar Zeita, north and northeast Hama.
Rami Abdurrahman, the head of the Britain-based Syrian Observatory for Human Rights, said airstrikes pummeled the area of the fighting, but also targeted southern Idlib, hitting at least four medical centers.
Abdurrahman said one old woman was killed near a hospital in Alteh, south of Idlib. The opposition-operated Qasioun News Agency said two hospitals were knocked out of service because of the strikes, and counted at least 30 airstrikes in northern Hama and southern Idlib since early Tuesday.
The Observatory chief said the offensive is the widest so far by the al-Qaida-linked Hayat Tahrir al-Sham and its allies, including Chinese fighters of the Turkistan Islamic Party.
Abdurrrahman said thousands of fighters are involved and that the target is to reach the government-controlled city of Hama. He said the insurgents seized two villages and used car bombs to attack pro-government forces.
The insurgents have repeatedly aimed for Hama, a city which sits on a highway linking the capital, Damascus, with the northern provinces and also borders the vital coastal region that is an Assad stronghold. Their last offensive was in March, and was followed by a government chemical attack on Khan Sheikhoun in Idlib that killed over 80 civilians.