BEIRUT (AP) — Insurgents led by an al-Qaida-linked group launched one of their widest offensives yet Tuesday against Syrian pro-government forces, which responded with heavy airstrikes targeting hospitals and first responders.
Pro-government media said the airstrikes targeted insurgent supply lines from the northwestern Idlib province, a stronghold of the al-Qaida-linked group.
Opposition activists and rescue workers said at least two civilians were killed. They said two hospitals, and two centers used by volunteer first responders known as the White Helmets, were rendered non-operational.
The offensive tests a newly announced "de-escalation zone" in Idlib, the latest of four such areas declared by Russia and Iran, which support the Syrian government, and Turkey, which backs the rebels. Fighting has largely subsided in the other three zones, near Damascus, in the central Homs province and in southern Syria.
The "de-escalation zones" have freed up Syrian troops and allied militias to battle the Islamic State group in the eastern Deir el-Zour province and other areas.
The Syrian government-affiliated Central Military Media outlet acknowledged the insurgent offensive just south of Idlib and said forces responded with intensive airstrikes and shelling, killing a number of insurgents.
Rami Abdurrahman, the head of the Britain-based Syrian Observatory for Human Rights, said airstrikes pummeled the front line but also targeted southern Idlib, hitting at least four medical centers.
The opposition-run Qasioun News Agency said two hospitals were knocked out of service because of the strikes. The White Helmets, also known as the Syrian Civil Defense, said two of its centers were also non-operational. The group counted at least 40 airstrikes in the area since early Tuesday.
Abdurrahman said the offensive is the widest so far targeting the government-held city of Hama. He said thousands of fighters, led by the al-Qaida-linked Hayat Tahrir al-Sham and its allies, including Chinese fighters of the Turkistan Islamic Party, took part in the offensive. He said the Alezzah Army, a rebel group formerly backed by the United States, was fighting alongside the other insurgents.
The insurgents seized two villages and used car bombs to attack pro-government forces, he said.
Insurgents have tried to advance on the nearby city of Hama on several occasions. During their most recent offensive, launched in March, a chemical attack widely blamed on government forces killed more than 80 civilians in Idlib.
Also on Tuesday, the U.S.-led coalition against the IS group confirmed that it had closed one of its two bases in southern Syria. Coalition spokesman Col. Ryan Dillon said that after the closure of the Zakaf base, coalition and allied Syrian forces are now only operating out of the larger Tanf base near the Jordanian and Iraqi borders.
The Zakaf base was established months ago as the U.S. expanded its presence in the area it was planning to use a launch pad for operations against IS in eastern Syria. But a Syrian government offensive, backed by Iran, essentially cut the base off.
U.S.-backed Syrian forces are meanwhile advancing in Deir el-Zour, just a few miles away from the Syrian government offensive, as the two sides race to secure the oil-rich province bordering Iraq. Dillon said U.S-trained Arab fighters in Tanf will eventually join that campaign.
Russia said Tuesday that the U.S.-backed forces were trying to slow the advance of Syrian government troops in Deir el-Zour by opening upstream dams to make it harder for them to cross the Euphrates River.
Maj. Gen. Igor Konashenkov, spokesman for Russia's Defense Ministry, said government forces have seized some 60 square kilometers (more than 23 square miles) on the east bank after crossing the river. But he said their progress was slowed by rapidly rising water levels over the past 24 hours.
Konashenkov said that in the absence of rains, the only explanation for the rapidly rising water was the opening of upstream dams. He said Syrian army units also reported being fired on from the north, where the U.S.-allied forces are located.
Associated Press writer Vladimir Isachenkov in Moscow contributed to this report.