Jeddah | Ukraine's President Volodymyr Zelenskyy arrived in Saudi Arabia ahead of an Arab summit on Friday, where he was set to address leaders who have remained largely neutral on Russia's invasion of his country, including many who maintain warm ties with Moscow.

Among those in attendance is Syrian President Bashar Assad, who has been welcomed back into the Arab fold 12 years after Syria was suspended at the start of its civil war.

Russian air strikes on civilian areas brought devastation to both countries, but in Syria they helped Assad cling to power.

The odd pairing of the two leaders in the same forum is the result of a recent flurry of diplomacy by Saudi Crown Prince Mohammed bin Salman, who is pursuing regional rapprochement with the same vigour he previously brought to the oil-rich kingdom's confrontation with its archrival Iran.

In recent months, Saudi Arabia has restored diplomatic ties with Iran, is ending the kingdom's years-long war against Iran-backed rebels in Yemen and led the push for Syria's return to the Arab League.

The Saudis have even offered to mediate between Ukraine and Russia, following a prisoner exchange deal they brokered last year.

Saudi state TV broadcast footage showing Zelenskyy arriving at the airport in his trademark brown fatigues and being greeted on the tarmac by Saudi officials.

In a tweet, he said he hopes to "enhance bilateral relations and Ukraine's ties with the Arab world.” The Ukrainian leader said he would address the summit in Jeddah and discuss the treatment of Muslim Tatars living under Russian occupation in the Crimean peninsula. The visit comes amid a whirlwind of international travel by the Ukrainian leader, but until now he has mostly visited allied countries.

Saudi Arabia pledged $400 million in aid to Ukraine earlier this year and has voted in favour of U.N. resolutions calling on Russia to end its invasion and refrain from annexing Ukrainian territory.

But it has resisted U.S. pressure to increase oil production in order to squeeze Russia's revenues, and like other Arab states has maintained warm ties with Moscow.

Leaders from the 22-member league, who were meeting in the Red Sea city of Jeddah, were also expected to focus on Sudan.

The East African country's top generals — both of whom have been backed by Saudi Arabia and other Arab states — have been battling each other across the country for over a month, killing hundreds and sparking an exodus from the capital, Khartoum, and elsewhere.

Gen. Abdel-Fattah Burhan, leader of the armed forces, and Gen. Mohamed Hamdan Dagalo of the paramilitary Rapid Support Forces, agreed to a pact in Jeddah last week that promised safe passage for civilians fleeing the fighting and protection for aid groups.

Saudi Arabia and the United States have meanwhile been leading international efforts to broker a lasting truce.

The fighting has killed over 600 people and caused tens of thousands to flee their homes.

The Arab League is also expected to reiterate its perennial support for the Palestinians at a time of soaring Mideast tensions.

In recent years, Assad's forces have recaptured much of Syria's territory from insurgents with help from Russia and Iran.

Saudi Arabia had been a leading sponsor of the opposition at the height of the war but pulled back as the insurgents were eventually cornered in a small pocket of northwestern Syria.

“Saudi Arabia's push to bring Syria back into the fold is part of a broader shift in the kingdom's approach to regional politics,” says Torbjorn Soltvedt, a leading Mideast analyst at the risk intelligence company Verisk Maplecroft.

“The previously adventurist foreign policy defined by the Yemen intervention and efforts to confront Iran are now being abandoned in favor of a more cautious approach,” he said.

Assad's first official meeting on Friday was with his Tunisian counterpart, Kais Saied, who is waging his own crackdown on dissent in the birthplace of the Arab Spring protests that in 2011 swept he region.

“We stand together against the movement of darkness,” Assad said, apparently referring to extremist groups that came to dominate the Syrian opposition as his country's civil war ground on, and which drew a large number of recruits from Tunisia.

The Saudi crown prince later welcomed each leader to the summit, including a smiling Assad wearing a dark blue suit.

The two shook hands and kissed cheeks before the Syrian leader walked into the hall.

There are some Arab holdouts to Damascus' rehabilitation, including gas-rich Qatar, which still supports Syria's opposition.

Qatar has said it won't stand in the way of the Arab consensus on readmitting Syria but would also not normalise bilateral relations without a political solution to the conflict.

Western countries, which still view Assad as a pariah over his forces' aerial bombardment and gas attacks against civilians during the 12-year civil war, have criticised his return to the Arab fold and vowed to maintain crippling sanctions.

That will likely continue to hamper any reconstruction.

Years of heavy fighting involving Assad's forces, the opposition and jihadi groups like the Islamic State group left entire villages and neighbourhoods in ruins.

U.S. lawmakers are rallying to block the Arab effort to bring Assad back into the international community. House Foreign Affairs Committee Chairman Michael McCaul, a Texas Republican, declared the U.S. “must use all of our leverage to stop normalisation" with Assad.

Democrats and Republicans on McCaul's committee advanced legislation this week that would bar any U.S. federal agency from recognising or carrying out normal relations with Syria's government as long as it's led by Assad, who came to power in 2000, following the death of his father.

The legislation would also plug holes in existing U.S. sanctions targeting Assad, and mandate the U.S. create a formal strategy to counter efforts by countries that do normalise relations with his government.

Lawmakers are taking a somewhat harder line than the U.S. administration has so far.

“Our position is clear. We are not going to normalise relations with the Assad regime and we certainly don't support others doing that,” the State Department's deputy spokesman Vedant Patel told reporters in Washington on Wednesday.

Patel said the administration is still committed to a U.N. Security Council resolution adopted in 2015 that endorsed a roadmap to peace drafted three years earlier.

But several rounds of talks held over the years between Assad's government and the opposition went nowhere, and he has had little incentive to compromise with the beleaguered insurgents since Russia entered the war on his side eight years ago.

Arab leaders appear to be focused on more modest goals, like enlisting Assad's help in countering militant groups and drug traffickers.