Jihadists and rebels have seized most of Aleppo, Syria’s second-largest city, including its airport, during a lightning assault that left over 320 people dead, a monitoring group reported on Saturday, as the international community voiced concern.

The Syrian Observatory for Human Rights, a UK-based NGO with an extensive network of sources in the war-torn country, reported that Russian airstrikes hit Aleppo early yesterday morning. These were the first such strikes since 2016, the year Damascus regained control of the strategically crucial city in northwestern Syria, with support from Moscow, among others.

Later in the afternoon, a “likely” Russian airstrike targeted “civilian vehicles” in a rebel-held sector of Aleppo, killing 16 civilians, according to the same source.

A photojournalist from Agence France-Presse (AFP) witnessed charred vehicles, bodies on the road, and one inside a car.

The scope of the fighting is the largest in years in Syria, where a devastating war erupted in 2011, drawing in various factions supported by regional and major powers, as well as foreign nations directly.

Thanks primarily to military support from Russia, Iran, and Lebanon’s Hezbollah, Assad’s regime launched a counteroffensive in 2015, gradually recapturing most of the country and fully reclaiming Aleppo in 2016.

Hayat Tahrir al-Sham (HTS), a group dominated by the former Syrian branch of al-Qaeda, and Syrian rebel factions, some backed by Turkey, launched an offensive on Wednesday, the same day a ceasefire agreement between Hezbollah and Israel in Lebanon took effect. The assault was launched from Idlib province, the last stronghold of anti-regime forces, which remains mostly outside Damascus’s control.

They captured dozens of villages before entering Aleppo on Friday.

“HTS and allied factions have taken most of Aleppo, including government buildings and prisons,” according to the Syrian Observatory for Human Rights.

Jihadists and rebels paraded through the streets, hoisted their flag at a police station, and tore down a portrait of Assad, as seen in footage obtained by AFP.

They also seized Aleppo’s international airport, the Observatory confirmed.

According to the NGO, the opposition forces also advanced in Idlib and Hama provinces (central Syria), taking control of “dozens of strategically significant villages without facing any resistance.”

The army retreated from the city of Hama, the Observatory reported, but a government source quoted by state media denied this.

The Syrian military acknowledged the presence of opposition fighters in “large parts” of Aleppo and reported “dozens of casualties,” both dead and wounded, in their ranks.

According to the latest toll from the Syrian Observatory for Human Rights, at least 327 people have been killed since Wednesday: 183 jihadists and rebels, 100 Syrian soldiers or allied fighters, and 44 civilians.

Iran reported yesterday that “terrorist elements” attacked its consulate in Aleppo.

Foreign Minister Abbas Araghchi is expected in Damascus later today, before heading to Turkey tomorrow.

Tehran has called for “coordination” with Moscow to repel the assault.

Baghdad stressed that Syria’s “security” and “stability” are “intricately linked” to the situation in Iraq.

France urged all parties to ensure the “protection of civilians” in Aleppo.

The White House stated that the regime is facing the consequences of its “refusal” to initiate a political transition process and its “dependence on Russia and Iran,” adding that the U.S. had “no involvement” in the jihadists’ and their allies’ offensive.

Northwestern Syria had experienced an uneasy calm in recent years following a ceasefire agreement reached after a regime offensive in March 2020, brokered by Russia and Turkey.

Jihadists and rebels imposed a 24-hour curfew from 5:00 PM yesterday (4:00 PM Greek time) for “residents’ safety.”

The director of the Syrian Observatory for Human Rights, Rami Abdel Rahman, told AFP that the opposition forces rapidly took control of vast areas of Aleppo “without encountering significant resistance.”

“The regime’s lines collapsed at an astonishing speed that caught everyone off guard,” said Dareen Khalifa, an analyst with the International Crisis Group.

HTS and its allied factions control most of Idlib province and parts of the neighboring provinces of Aleppo, Hama, and Latakia.

The Turkish military, which controls areas of Syrian territory along the border between the two countries, called on Friday for an “end” to “attacks” in Idlib, following airstrikes by Russia and Syria.

Since the war erupted in spring 2011, triggered by the brutal crackdown on protests demanding democratic reforms, it has claimed over half a million lives and displaced millions more as internally displaced persons or refugees.