Mr Assad was suspended by the alliance after his crackdown on pro-democracy protests led to the breakout of civil war in 2011.

More than 500,000 people have died since then and more than half of the country's 22 million pre-war population have had to flee their homes.

Speaking in the host city of Jeddah in Saudi Arabia, Mr Assad described his reinstatement as a "historic opportunity" to address crises across the Arab world.

The decision to allow him back in is part of Saudi Crown Prince Mohammed bin Salman's bid to improve relations in the region, after he pushed to restore diplomatic ties with longstanding rival Iran earlier this year.

It also comes after the devastating earthquake in February that killed around 50,000 people in Turkey and 8,000 in Syria.

earlier this month British foreign secretary Jams Cleverley said: "The UK is very uncomfortable with Syria's readmission to the Arab League.. ultimately [it] is a decision for the membership of the Arab League."

"there needs to be conditionality if they choose to take this course of action.. as they have done. It needs to be conditional on some fundamental changes of behaviour from Damascus and from the Assad regime"

Ukrainian President Volodymyr Zelenskyy was also in Jeddah, following other surprise in-person engagements in London, Vatican City and Paris.

Until now he has largely only left the country to visit Ukraine's allies, but on Friday Mr Zelenskyy accused some of the 22 member states of "turning a blind eye" to Russia's invasion.

Seemingly invoking the region's own difficult past, he said he hoped they would understand Ukraine "will never submit to any foreigners or colonisers".

"That's why we fight," he added.

Mr Zelenskyy criticised Iran for supplying the Kremlin with drones and also mentioned the plight of ethnic Muslim Tatars living under Russian occupation in Crimea.

Saudi Arabia has said it is "is ready to exert efforts for mediation between Russia and Ukraine", but has fallen short of demands to increase its oil production to help cripple Russia.

Qatar leaves before Assad speech

Not everyone was pleased to welcome Mr Assad back, however.

Emir of Qatar, Sheikh Tamim bin Hamad al Thani, left the summit before Mr Assad spoke.

An Arab official described Tamim's visit as a "courtesy" and said he did not hold any bilateral meetings.

The US and its Western allies have also expressed shock at the Syrian leader's invitation, with much of the world regarding him as a war criminal.

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US Department of State spokesman Vedant Patel said America "does not believe that Syria merits readmission".

Sudan, where the conflict between two warring generals is costing hundreds of lives, was also on the agenda.

League members support both sides and last week Jeddah hosted negotiations that ended in the promise of safe passage for civilians to flee the fighting, as well as protection for aid workers.

Support for Palestinians was also discussed as tensions escalate in the Middle East.