Opposition forces have captured the city of Hama in central Syria, the latest victory for the rebels since they launched a lightning offensive eight days ago and a major blow to President Bashar al-Assad.

The Syrian army said opposition forces entered Hama on Thursday after intense fighting, prompting its units to withdraw from the city.

The army said in a statement it was redeploying its forces “to preserve civilian lives and prevent urban combat” after intense clashes.

Abu Mohammed al-Julani, the leader of the most powerful opposition armed group Hayat Tahrir al-Sham (HTS), a former al-Qaeda affiliate, declared that opposition forces had full control over Hama.

Al Jazeera’s Resul Serdar said the taking of Hama was a “major development”.

“In just over a week, they have managed to take full control of Syria’s second-largest city, Aleppo, and now the fourth-largest city,” Serdar said, reporting from the Turkish city of Kilis, on the border with Syria.

The opposition also took over the city’s military airport, Serdar said, “one of the largest in Syria” that has been used by government forces to launch strikes against rebels.

“Today, they managed to breach the regime’s front lines and get into the city from the eastern part,” Serdar said, adding that a “significant” number of residents in Hama fled the city.

Beginning last Wednesday, opposition groups led by HTS pushed south from areas under their control in northwest Syria, capturing Aleppo over the weekend before reaching a strategic hill just north of Hama on Tuesday and advancing towards the city’s east and west flanks.

The rapid collapse of Syrian government control in the north appears to reveal a shift in the balance of power since the Lebanese armed group Hezbollah, a lynchpin of al-Assad’s battlefield force, suffered heavy losses in its war with Israel.

Al-Assad relied heavily on Russian and Iranian backing throughout the most intense years of Syria’s more-than-13-year war, with allied forces helping him to claw back most territory and the biggest cities before the front lines froze in 2020 with a ceasefire.

But Russia has been focused on its war in Ukraine since 2022, while many senior leaders in Hezbollah, the most powerful Iran-aligned force, were killed in Israeli attacks in recent months.

In a video statement, al-Julani warned against any involvement by another Iran-aligned force – Iraq’s Hashd al-Shaabi paramilitary coalition.

Some Iraqi fighters entered Syria early this week to support Assad, Iraqi and Syrian sources said. The Hashd al-Shaabi has mobilised along the border with Syria saying this was purely preventative in case of spillover into Iraq.

“We urge him [Iraq’s prime minister] again to keep Iraq away from entering into the flames of a new war tied to what is happening in Syria,” Julani said.

Why is Hama significant?

Robert Geist Pinfold, from Durham University, said if the opposition manages to “hold Hama”, it would have both symbolic and strategic significance.

“Hama is the birthplace of Sunni, armed, Islamist resistance against the Baath party … of Bashar al-Assad and his father,” Pinfold told Al Jazeera.

The capture of Hama would also “open up the road to Homs, it would open up the road to Damascus,” he said. Homs is the main central city and functions as a crossroads connecting Syria’s most populous regions.

Hama is also critical to the control of two major towns with sizeable minority religious communities; Muhrada, which is home to many Christians, and Salamiya, where there are many Ismaili Muslims.

Hama province also borders the coastal region of Latakia, a main base of popular support for al-Assad.

Prior to Thursday, Hama had stayed in government hands throughout the war, which erupted in 2011 as a rebellion against al-Assad.

Samuel Ramani, an associate fellow at the Royal United Services Institute, said Damascus was likely temporarily redeploying forces to “avoid major losses of lives under urban combat, and then they’ll regroup with the required military assistance and try to retake” Hama.

“But I think it’s going to be very hard for the Russians and the Syrians to be able and regain momentum immediately, because now that the opposition is gaining control of Hama, they’re going to be launching a major offensive on Homs,” Ramani told Al Jazeera.

“If Homs is taken, Damascus is under serious threat.”

Russia is assessing the situation in Syria and is in constant contact with the Syrian authorities, Kremlin spokesperson Dmitry Peskov said on Thursday.

“At the moment, we are closely monitoring what is happening in Syria. We are in constant dialogue with our Syrian friends, with Damascus,” Peskov told reporters.

“Depending on the assessment of the situation, we will be able to talk about the degree of assistance that is needed by the Syrian authorities to cope with the militants and eliminate this threat.”