Syria s President Bashar al-Assad (2-L) receiving the leader of Palestinian militant group Islamic Jihad, Ziad al-Nakhala (R) Hamas chief of Arab relations, Khalil al-Hayya (2-R) and secretary general of the Popular Front for the Liberation of Palestine, Talal Naji (L), in the capital Damascus, on October 19, 2022. AFP
The Islamist group, which controls the Gaza Strip, was long one of Syria's closest allies, in large part due to a shared enmity towards Israel.
But it left Syria in 2012 after condemning the Assad government's brutal suppression of protests in March 2011, which triggered the country's descent into civil war.
"This is a glorious and important day, in which we come back to our dear Syria to resume joint work," Hamas chief of Arab relations Khalil al-Hayya told reporters in Damascus.
"This is a new start for joint Palestinian-Syrian action," he said after meeting Assad along with other representatives of Palestinian factions.
Hamas and Assad have agreed to "move on from the past and look to the future," al-Hayya added.
Wednesday's meeting with Assad "is in line with the broader rapprochement between Hezbollah and Hamas evident in Lebanon over the past year or more," said Maha Yahya of the Carnegie Middle East Center.
The moves come amid fundamental shifts in Middle East relationships, including the Islamist group's long-time ally Turkey restoring full diplomatic ties with Israel in August.
Charles Lister, Director of the Syria Program at the Middle East Institute, said rapprochement is the "only logical move" Hamas could take.
"Given the prevailing regional trend of Arab engagement with Israel, it's not surprising to see Hamas' leadership in Gaza seeking to re-enhance and amplify their role within the Axis of Resistance," he told AFP.
Aron Lund, a fellow with the Century International think-tank, said the thaw has "been propelled by the hostile regional attitude to Hamas and by Israel's normalization with several Arab states."
"Hamas simply doesn't have the luxury of being able to ignore or oppose the Syrian government indefinitely," Lund said.
Al-Hayya said there was consensus among Hamas leadership and supporters over the resumption of ties with Syria -- a move also backed by the Palestinian group's foreign sponsors.
"All the states we notified of our decision were welcoming and supportive of the move, including Qatar and Turkey, who encouraged us to take the step," al-Hayya said.
Turkey supports rebels against the government in Syria's civil war, but has lately signalled a willingness to reconcile with Damascus.
According to Lund, Hamas' rapprochement with Damascus "seems to have been facilitated by the fact that several other Arab states have reconnected with Assad's regime."
"Turkey's recent softening of tone will also have helped," he told AFP.
The Syrian presidency said Assad met a delegation of Palestinian leaders without mentioning the restoration of ties with Hamas.
But the presidency published a video of Assad and Al-Hayya holding hands as they walked with other Palestinian officials.
The two-day Hamas visit to Syria comes after the Islamist group signed a reconciliation deal with its Palestinian rival Fatah in Algiers last week, vowing to hold elections by next October in a bid to settle a 15-year intra-Palestinian rift.
A Hamas leader told AFP that the group, which was headquartered in the Syrian capital before leaving the country, plans to reopen its Damascus office.
But it was "too early" to talk about relocating its headquarters to the Syrian capital, said the official who spoke on the condition of anonymity.
The thaw between Hamas and Damascus was brokered by Tehran and Hezbollah, a senior Hamas source said.
For the past decade, Syrian officials had accused Hamas of betrayal.
In a 2013 speech, Assad had accused Palestinian groups he did not identify of treating the country like a "hotel" that they leave "when conditions are tough" in a thinly-veiled reference to Hamas.
Hamas has its origins in the transnational Muslim Brotherhood, whose Syrian branch was one of the leading factions in the armed opposition after Syria's civil war broke out.
Hamas officials have said they broke ties with the Brotherhood in 2017.