ERBIL, Kurdistan Region of Iraq - Violent clashes continue in northwestern Syria four days after rebel groups, led by Hay’at Tahrir al-Sham (HTS), launched a surprise offensive against the Syrian army in Aleppo and Idlib countryside, triggering one of the bloodiest escalations in the Syrian civil war in years.

The Syrian army said in a statement on Saturday that their forces continue to confront the attack from the opposition groups, which have used medium and heavy weaponry in their offensive, and “rely on large groups of foreign armed terrorists.”

The army claimed to have inflicted “massive losses” upon the armed groups, killing and injuring hundreds, destroying dozens of armed vehicles, and shooting down at least 17 drones.

Opposition-affiliated media have reported that the groups have seized control of large territories of Aleppo city, including most of the western neighborhoods and a large number of southern, northern, and central neighborhoods.

In a statement early Saturday, the groups announced controlling Aleppo Citadel in the center of the ancient city, as well as the Umayyad Mosque. The rebel groups vowed to secure Aleppo “militarily and security-wise” within the coming hours, and then “liberate” the city entirely.

The Syrian army statement claimed to have recaptured some of the positions that were infiltrated by the groups, accusing the opposition media of publishing misleading information and reports “aimed at terrorizing citizens.”

The Syrian Observatory for Human Rights (SOHR), a UK-based war monitor, on Saturday claimed that the HTS and affiliated groups have seized control of several neighborhoods and nearly 65 villages and towns over the past four days.

The war monitor also reported that Syrian and Russian warplanes launched raids in neighborhoods in western Aleppo overnight for the first time since 2016, killing at least 20 HTS militants.

Over 300 people have so far been killed as a result of the clashes, including at least 155 HTS members, 100 Syrian army soldiers, and 24 civilians, according to SOHR.

Iraq says borders ‘impenetrable’

Iraqi border forces commander Mohammed al-Su’aidi on Saturday said that Iraq’s borders with Syria were completely fortified and “impenetrable”, emphasizing the forces’ preparedness to counter any attacks.

The statement from Su’aidi followed comments from Fadi al-Shammari, advisor to the Iraqi Prime Minister, who stressed that Iraqi armed forces are “fully prepared” to confront any threats that would put the country and its people at risk.

“The activity of terrorist groups in northwestern Syria is considered a dangerous development in terms of (timing, readiness, and armament), which requires caution, vigilance and full readiness,” wrote Shammari on X late Friday.

Iraqi military spokesperson Yehia Rasool on Friday said that the borders with Syria are “largely fortified and secure,” adding that intelligence services are monitoring the movement of “terrorist” groups and if they try to cross the border there will be “a strong and firm response.”

Tehran, Moscow reiterate support for Damascus

Iranian Foreign Minister Abbas Araghchi held a phone call with his Syrian counterpart Bassam al-Sabbagh on Friday, reiterating Tehran’s support for the Syrian government, and calling the reactivation of the rebel groups in Syria an American-Israeli plot.

Iran has been a main supporter of Syrian President Bashar al-Assad’s regime throughout the Syrian civil war. Thousands of Islamic Revolutionary Guard Corps (IRGC) soldiers were deployed to Syria after 2011, and dozens of other Iran-backed armed groups remain active in the country.

Kremlin spokesperson Dmitry Peskov called the escalations in Syria "an attack on Syrian sovereignty," and said that Moscow is in favor of Syrian authorities "bringing order to the area and restoring constitutional order as soon as possible.”

Russia has been Assad’s most important military ally, helping turn the tides in favor of the Syrian president in the civil war when it intervened in 2015.