American Marconi Wireless News - Syrians search for loved ones while rejoicing in Assad's fall

Assad fled the country as Islamist-led rebels swept into the capital, bringing to a spectacular end on Sunday five decades of brutal rule by his clan over a country ravaged by one of the deadliest wars of the century.

He oversaw a crackdown on a democracy movement that erupted in 2011, sparking a war that killed 500,000 people and forced half the country to flee their homes.

At the core of the system of rule that Assad inherited from his father Hafez was a brutal complex of prisons and detention centres used to eliminate dissent by jailing those suspected of stepping out of the ruling Baath party's line.

On Monday, rescuers from the Syrian White Helmets said they were searching for secret doors or basements in Saydnaya prison, looking for any detainees who might be trapped.

"We are working with all our energy to reach a new hope, and we must be prepared for the worst," the organisation said in a statement.

While Syria has been at war for 13 years, the government's collapse ended up coming in a matter of days, with a lightning offensive launched by the Islamist Hayat Tahrir al-Sham (HTS).

Rooted in Syria's branch of Al-Qaeda, HTS is proscribed by Western governments as a terrorist group.

While it remains to be seen how HTS operates now that Assad is gone, it has sought to moderate its image and to assure Syria's many religious minorities that they need not fear.

In central Damascus on Monday, despite all the uncertainties for the future, the atmosphere was filled with joy.

"It's indescribable, we never thought this nightmare would end, we are reborn," 49-year-old Rim Ramadan, a civil servant at the finance ministry, told AFP.

"We were afraid for 55 years of speaking, even at home, we used to say the walls had ears," Ramadan said, as people honked their car horns and rebels fired their guns into the air.

"We feel like we're living a dream," she added.

- 'Historic opportunity' -

During the offensive launched on November 27, rebels wrested city after city from Assad's control, opening the gates of prisons along the way and freeing thousands of people, many of them held on political charges.

Social media groups were alight with Syrians sharing images of detainees reportedly brought out from the dungeons, in a collective effort to reunite families with their loved ones, some of whom had been missing for years.

Others, like Fadwa Mahmoud, whose husband and son are missing, posted calls for help finding their loved ones.

"Where are you, Maher and Abdel Aziz, it's time for me to hear your news, oh God, please come back, let my joy become complete," wrote Mahmoud, herself a former detainee.

US President Joe Biden said Assad should be "held accountable" as he called his downfall "a historic opportunity" for the people of Syria.

"The fall of the regime is a fundamental act of justice," he said.

But he also cautioned that hardline Islamist groups within the victorious rebel alliance would face scrutiny.

"Some of the rebel groups that took down Assad have their own grim record of terrorism and human right abuses," Biden said.

The United States has taken note of recent statements by the rebels suggesting they were adopting a more moderate posture, but Biden said: "We will assess not just their words, but their actions."

Amnesty International also called for perpetrators of rights violations to face justice, with its chief Agnes Callamard urging the forces that ousted Assad to "break free from the violence of the past".

"Any political transition must ensure accountability for perpetrators of serious violations and guarantee that those responsible are held to account," UN rights chief Volker Turk said on Monday.

- Where is Assad? -

How Assad might face justice remains unclear, especially after Russia refused on Monday to confirm reports by Russian news agencies that he had fled to Moscow.

The Syrian embassy in Moscow raised the flag of the opposition, and the Kremlin said it would discuss the status of its bases in Syria with the new authorities.

Russia played an instrumental role in keeping Assad in power, directly intervening in the war starting in 2015 and providing air cover to the army on the ground as it sought to crush the rebellion.

Iran, another key ally of Assad, said it expected its "friendly" ties with Syria to continue, with its foreign minister saying the ousted president "never asked" for Tehran's help against the rebel offensive.

Turkey, historically a backer of the opposition, called for an "inclusive" new government in Syria, as the sheer unpredictability of the situation began to settle in.

"It is not just Assad's regime falling, it is also the question of what comes in its place?" said Aron Lund, a specialist at the Century International think tank.

While Syria's war began with a crackdown on grassroots democracy protests, it morphed over time and drew in jihadists and foreign powers backing opposing sides.

Israel, which borders Syria, sent troops into a buffer zone after Assad's fall, in what Foreign Minister Gideon Saar described as a "limited and temporary step".

A Syria war monitor said Monday that Israel also carried out overnight strikes on Syrian military positions and depots in several parts of the country.

And in northern Syria, a Turkish drone strike on a Kurdish-held area killed 11 civilians, six of them children, according to the Syrian Observatory for Human Rights war monitor.

P.Mathewson--AMWN