Rebel forces in Syria said they were advancing on the capital Damascus after capturing four more cities in the past 24 hours, as the insurgents’ lightning advance continued and threatened President Bashar al-Assad’s grip on power.

In the early hours of Sunday morning local time, the Islamist Hayat Tahrir al-Sham group (HTS) said via messaging app Telegram that rebel forces had entered Damascus and reached Sednaya Prison, a government facility they described as ” “Human Slaughterhouse” is the name given to the human rights group Amnesty International.

“Our forces have begun to enter the capital Damascus,” the group said in a statement. In a follow-up statement, the group said it was “the end of the era of injustice in Sednaya Prison.”

The group previously claimed it had taken over the city of Homs in the north of the country on Saturday.

HTS leader Abu Mohammed Al-Jolani released a video claiming government forces there had withdrawn without a fight, and the rebel group later released a statement: “Our eyes are on the capital Damascus.”

Lightning advance by rebel groups

In total, the insurgent group claimed it had taken three more Syrian towns over the past day – including Daraa, Queinetra and Sweida – in a series of quick advances by opposition fighters that largely encountered little resistance from government forces.

Over the course of Saturday, as rebel forces moved, the Syrian army withdrew from large parts of southern Syria, leaving more areas of the country, including two provincial capitals, under rebel control, according to the military and an opposition war monitor.

In a statement released earlier Saturday, the Syrian government denied that Assad had fled the country, calling media reports to the contrary “rumors and fake news.”

US intelligence had prepared for Assad’s front line to collapse under rebel pressure, and the US had information that Assad’s family had left the country for Moscow.

Earlier this week, government forces withdrew from Hama, Syria’s fourth-largest city, located between the capital Damascus in the south and Aleppo, Syria’s second-largest city, in the north.

Aleppo fell victim to the rebels’ lightning offensive on November 29th. Hama was one of the few major cities that did not fall into the hands of anti-government forces after the unsuccessful revolution against Assad’s rule in 2011.

Who are the Syrian rebels?

The rebel offensive is being led by HTS and a group of Turkish-backed Syrian militias, the Syrian National Army.

HTS, whose roots lie in Al-Qaeda, is classified as a terrorist organization by the US

But the group said it had cut ties with al-Qaeda in recent years and sought to reinvent itself by focusing on promoting civilian government and military actions, according to the Associated Press.

If Assad flees the country and HTS gains control of Syria’s government institutions, it is unknown how they will attempt to govern.

“Are they going to resort to it more when it was linked to al-Qaeda?” Javed Ali, an associate professor at the University of Michigan’s Ford School of Public Policy, said during an appearance on ABC News Live. “Or will it look more like the Taliban in Afghanistan – who are Islamist and conservative but largely unconcerned with threatening their neighbors or using their land as a launching pad for attacks against the West.”

What officials say about the situation in Syria

Ali called the developments a “catastrophic loss” for Iran, which has long supported the Assad regime, and a “black mark” for the Russian government, which has also supported Assad.

Citing media reports, Ali said both countries had apparently withdrawn advisers and equipment from the country.

“If these withdrawals continue on both the Iranian and Russian sides, basically only the Syrian military and security forces will be left,” he said. “And similar to what we saw in Afghanistan in 2021, they are unlikely to be able to hold back against HTS and all the other rebel groups that are currently on the outskirts of Damascus.”

President-elect Donald Trump weighed in on developments in the Syrian civil war on his social media platform Truth Social on Saturday, saying the US should stay out of the matter entirely.

“Syria is a mess, but it is not our friend, And the United States should have nothing to do with it. This is not our fight. LET IT PLAY. Don’t get involved!” Trump posted.

In the post, Trump noted that Russia, which has long supported Assad’s regime, was “tied down in Ukraine” and appeared unable to intervene in Syria. Trump said that ousting Assad was “actually the best thing that could happen to the Russian government.”

Meanwhile, Russian Foreign Minister Sergei Lavrov commented on the rebel offensive in Syria early Saturday, saying Russia would counter it “in every possible way,” but Russia “will actively advocate the need to resume dialogue with the opposition,” that is, between the government and Turkey rebels.