Syria's second-largest city Aleppo has fallen from government control for the first time since the country's conflict began more than a decade ago, a war monitor said Sunday, after a surprise advance by rebels.
An Islamist-dominated rebel alliance has pressed a lightning offensive against forces of the Iranian- and Russian-backed Syrian government since Wednesday, the same day a fragile ceasefire took effect in neighbouring Lebanon between Israel and the Iran-backed Hezbollah group after two months of all-out war.
The Syrian army -- supported by Russian air power -- had recaptured in 2016 rebel-held areas of Aleppo, a city dominated by its landmark citadel.
Damascus also relied on Hezbollah fighters to regain swathes of Syria lost to rebels early in the war which began in 2011 when the government crushed protests. But Hezbollah has taken heavy losses in its fight with Israel.
The jihadist Hayat Tahrir al-Sham and allied rebel factions "control Aleppo city, except the neighbourhoods controlled by the Kurdish forces," Rami Abdel Rahman, head of the Britain-based Syrian Observatory for Human Rights, told AFP.
For the first time since the conflict started, "Aleppo city is out of control of Syrian regime forces," Abdel Rahman said.
Several northern districts inside Aleppo are predominantly inhabited by Syrian Kurds under authority of the People's Protection Units (YPG), the main component of the Syrian Democratic forces.
The SDF are the de facto army in the semi-autonomous Kurdish region of northeast Syria. They are a US-backed force that spearheaded fighting against the Islamic State group jihadists before IS's territorial defeat in Syria in 2019.
Separately, the jihadist Hayat Tahrir al-Sham and allied rebel factions seized Aleppo's airport and dozens of nearby towns on Saturday after overrunning most of Aleppo, the Observatory said.
Damascus ally Moscow responded with its first air strikes on Aleppo since 2016.
Prior to this offensive, HTS, led by Al-Qaeda's former Syria branch, already controlled swathes of the Idlib region, the last area outside President Bashar al-Assad's government control, in Syria's northwest.
HTS also held parts of neighbouring Aleppo, Hama and Latakia provinces. Allied Turkish-backed rebel factions have also been taking part in the offensive.
The fighting has killed more than 370 people, most of them combatants but also including at least 48 civilians, according to the Observatory, which has a network of sources inside Syria.
The Observatory said rebel advances came with little resistance.
AFP images showed fighters posing with seized tanks.
The Observatory on Sunday said the army strengthened its positions around Syria's fourth largest city Hama, about 230 kilometres (140 miles) south of Aleppo, and sent reinforcements to the north of the surrounding province.
Syria's defence ministry said army units in Hama province "reinforced their defensive lines with diverse means of fire, equipment and personnel", fighting to prevent a rebel advance.
Rebels took dozens of towns across the north, including Khan Sheikhun and Maaret al-Numan, roughly halfway between Aleppo and Hama, the Observatory said.
Some welcomed the rebels' arrival.
"Yesterday was my wedding but I didn't distribute sweets," Khaled al-Yussef said, holding up pastries beside a car. "I'm distributing them today in celebration of the liberation of Maaret al-Numan."
But in Idlib on Sunday, bodies lay in a hospital and vehicles were torched in the street, AFP images showed, after what the Observatory called Russian air strikes.
Air strikes also occurred Saturday in Aleppo, where an AFP photographer saw charred cars, including a minibus. Inside one car, the body of a woman lay slumped in the back seat with a handbag beside her.
Russian air strikes on parts of Syria's second city are the first since 2016.
Aaron Stein, president of the US-based Foreign Policy Research Institute," said "Russia's presence has thinned out considerably and quick reaction air strikes have limited utility".
He said the rebel advance is "a reminder of how weak the regime is".
Syria's "reliance on Russia and Iran", along with its refusal to move forward with a 2015 peace process outlined by the UN Security Council, "created the conditions now unfolding", said US National Security Council spokesman Sean Savett.
The United States maintains hundreds of troops in Syria's northeast as part of an anti-jihadist coalition.
Iran's top diplomat, Foreign Minister Abbas Araghchi, left Tehran for Damascus to deliver what state media said would be a message of support for Syria's government and armed forces.
Araghchi again called the surprise rebel offensive a plot by the United States and Israel and vowed that "the Syrian army will once again win".
Assad vowed to defeat the "terrorists", however big their attacks.
"Terrorism only understands the language of force, and that is the language which we will break it and eliminate it with, whoever its supporters and sponsors are," he said.
Russia, whose air support was previously decisive in helping Syria's government win back lost territory, joined Iran in expressing "extreme concern" over their ally's losses.
"Strong support for the sovereignty and territorial integrity of the Syrian Arab Republic was reaffirmed," the Russian foreign ministry said in a summary of a call between its top diplomat, Sergei Lavrov, and Araghchi.
Since 2020, the Idlib rebel enclave has been subject to a Turkish- and Russian-brokered truce that had largely been holding despite repeated violations.
Lavrov also spoke with his Turkish counterpart Hakan Fidan on Saturday and agreed on the need to "coordinate joint action to stabilise the situation", Moscow said.
