UK Prime Minister Sir Keir Starmer has welcomed the fall of Bashar al-Assad’s “barbaric regime” in Syria, as he called for the restoration of “peace and stability”.

The ousted Syrian president – who Russian state media report is in Moscow having been granted asylum by Russia – fled the country after his government fell to a lightning rebel offensive early on Sunday.

Sir Keir said the Syrian people “had to put up with [Assad’s] brutal regime for far, far too long”.

When asked if the government would engage with rebel group Hayat Tahrir al-Sham (HTS), set up as an affiliate of al-Qaeda and proscribed as a terrorist group by the UK, he said it was “early days” but that there needed to be a “political solution”.

“The developments in Syria in recent hours and days are unprecedented, and we are speaking to our partners in the region and monitoring the situation closely,” Sir Keir said on Sunday, shortly after arriving in the United Arab Emirates for a visit unrelated to events in Syria.

“The Syrian people have suffered under Assad’s barbaric regime for too long and we welcome his departure.

“Our focus is now on ensuring a political solution prevails, and peace and stability is restored.”

He also called on “all sides” to protect civilians and minorities, and “ensure essential aid can reach the most vulnerable” in the coming hours and days.

Shadow Foreign Secretary Priti Patel said: “Our first priority must be the Syrian people. Syrians need to be protected – all communities and groups.”

Lib Dem leader Sir Ed Davey described Assad as “a vile dictator who used chemical weapons against him own people” in a post on X.

He added the UK must “do what we can to ensure the protection of minority groups and ultimately an orderly transition of power with free and fair elections”.

Deputy Prime Minister Angela Rayner earlier told the BBC’s Sunday with Laura Kuenssberg programme that the UK wanted to see “a political solution along the lines of UN resolution, and we’re working with our allies”.

Asked if HTS would be better than Assad, Rayner said “we’ve got to have a government in Syria, a political solution, that protests civilians and infrastructure”.

The Islamist group, set up 13 years ago as a direct affiliate of al-Qaeda, drove the rebels’ rise to power in Syria in recent weeks.

It previously publicly broke ranks with al-Qaeda, although it remains proscribed as a terrorist group by the UK, as well as the UN, the US, Turkey and other countries.

Questions remain over whether it has completely renounced those links, but its message in the run-up to Assad’s deposition has been one of inclusiveness and a rejection of violence.

• Watch: The final hours of the Assad regime
• HTS leader not only player in Syria’s fast-changing future

Former head of MI6 Sir John Sawers told Sky News: “I think Abu Mohammed al-Jawlani, the leader, has made great efforts over the last 10 years to distance himself from those terrorist groups and certainly the actions we’ve seen of [HTS] over the last two weeks has been those of a liberation movement, not of a terrorist organisation.”

He added: “It would be rather ridiculous, actually, if we’re unable to engage with the new leadership in Syria because of a proscription dating back 12 years.”

The prime minister’s pre-planned visits to the United Arab Emirates and Saudi Arabia for meetings on Monday are unrelated to events in Syria.

The government said Sir Keir is pursuing closer ties with the two countries to increase investment, deepen defence and security ties, and drive growth and new opportunities to benefit working people.

The UK government had been evacuating its citizens from Syria over the weekend before the fall of Damascus overnight.

On Sunday, hundreds of Syrians in Manchester celebrated Assad’s demise by singing, dancing and crying in the city centre, while dozens of people also gathered in Belfast to celebrate the end of his regime.