Bashar al-Assad's 24-year authoritarian rule has ended, Syrian rebels have said in their first announcement on state television following a lightning offensive that took the world by surprise.
Syria's army command notified officers on Sunday that Assad's regime had ended, a Syrian officer who was informed of the move told Reuters.
But the Syrian army later said it was continuing operations against "terrorist groups" in the towns of Hama and Homs and Deraa countryside.
Assad, who had crushed all forms of dissent and jailed thousands, flew out of Damascus for an unknown destination earlier on Sunday, two senior army officers told Reuters, as rebels entered the capital with no sign of army deployments.
"We celebrate with the Syrian people the news of freeing our prisoners and releasing their chains and announcing the end of the era of injustice in Sednaya prison," the rebels said, referring to a large military prison on the outskirts of Damascus where the Syrian government detained thousands.
Thousands of people in cars and on foot congregated at a main square in Damascus waving and chanting "freedom" from a half-century of Assad family rule, witnesses said.
The dramatic collapse marks a seismic moment for the Middle East, ending the family's iron-fisted rule over Syria and dealing a massive blow to Russia and Iran, which have lost a key ally at the heart of the region.
The pace of events has stunned Arab capitals and raised fears of a new wave of regional instability.
A Syrian Air plane took off from Damascus airport about the time the capital was reported to have been taken by rebels, according to data from the Flightradar website.
The aircraft initially flew towards Syria's coastal region, a stronghold of Assad's Alawite sect, before making an abrupt U-turn and flying in the opposite direction for a few minutes - before disappearing off the map.
Reuters could not immediately ascertain who was on board.
Two Syrian sources said there was a high probability Assad had been killed in a plane crash if the plane had taken a surprise U-turn and disappeared off the map as the Flightradar data showed.
"It disappeared off the radar, possibly the transponder was switched off, but I believe the bigger probability is that the aircraft was taken down," one Syrian source said without elaborating.
The head of Syria's main opposition group abroad, Hadi al-Bahra Syrian, declared Damascus was now "without Bashar al-Assad".
As Syrians expressed joy, Prime Minister Mohammad Ghazi al-Jalali said he was ready to support the continuity of governance and prepared to co-operate with any leadership chosen by the Syrian people.
US President Joe Biden and his team were monitoring the "extraordinary events in Syria" and were in touch with regional partners, the White House said.
The front lines of Syria's complex civil war were dormant for years before Islamists once affiliated with Al Qaeda burst into action.
The rebels posed the biggest challenge to Assad, who had survived years of gruelling war and international isolation with the help of Russia, Iran and Lebanon's Hezbollah.
But Assad's allies were focused on and weakened by other crises, leaving Assad at the mercy of his opponents with an army that was not prepared to defend him.
Syrian rebel leader Ahmed al-Sharaa said on Sunday it was prohibited to go near public institutions that he said would remain under the supervision of the "former prime minister" until they were officially handed over.
Israel, which has severely weakened the Iran-backed groups Hezbollah in Lebanon and Hamas in Gaza, will likely celebrate the fall of Assad, another of Iran's key regional allies.
However, the prospects of an Islamist group ruling Syria will likely raise concerns.
Hayat Tahrir al-Sham commander Abu Mohammed al-Golani, the main rebel leader, urged fighters not to harm "those who drop their arms".
There have not been reports of reprisals in Aleppo, which the rebels captured a week ago.
Syrian rebel commander Hassan Abdul Ghani said in a statement early Sunday that operations were ongoing to "completely liberate" the countryside around Damascus and rebel forces were looking toward the capital.
In one suburb, a statue of Assad's father, the late President Hafez al-Assad, was toppled and torn apart.
Qatar, Saudi Arabia, Jordan, Egypt, Iraq, Iran, Turkey and Russia issued a joint statement saying the crisis was a dangerous development and calling for a political solution.
Syria's civil war, which erupted in 2011 as an uprising against Assad's rule, dragged in big outside powers, created space for jihadist militants to plot attacks around the world and sent millions of refugees into neighbouring states.
