By John Lyons, global affairs editor, ABC
Syrian President Bashar al-Assad ousted as rebels take Damascus
Analysis - The Middle East has changed dramatically in just eight days.
Whether the regime of Syria's leader Bashar al-Assad is finished or just seriously wounded, he is now a leader with little authority.
A rebel army has been able to take swathes of the country, storming into Damascus and tearing down a picture of Hafez al-Assad, the man who set up the brutal regime.
Whatever the final outcome of the chaos in Syria, the last week has seen an extraordinary upheaval.
Russia and Iran take a hit
The big losers are Russia and Iran. They have both been instrumental in helping to prop up the regime since uprisings began in 2011.
For Russia, Syria is its strongest ally in the Middle East. It gives Moscow influence in the region.
Assad has allowed Russia to have a naval base in Tartous and an air base in Latakia in return for Moscow's support. This gave Russia a key strategic naval presence in the Mediterranean and air capability across the region.
For Iran, it breaks the Shia crescent from Iran, through Syria to Lebanon. The Assad regime was Alawite, an offshoot of Shia. Its closeness to Iran made it enemies of Israel, the US and Saudi Arabia.
How Assad fell
Two weeks ago, the Assad regime in Damascus appeared as solid as any regime in the Middle East. It had faced a major challenge in 2011 when an uprising began in the southern city of Deraa, with similar protests occurring around the country.
The Assad family has ruled over Syria with an iron fist for 54 years - first Hafez al-Assad and then his son, Bashar.
Bashar al-Assad cracked down on those protests with brutality, which in turn set off a civil war across the country.
Iran and Russia helped Assad cling to power. Iran volunteered fighters from its proxy, Hezbollah. Those Hezbollah fighters proved to be effective, crushing many of those trying to bring down Assad.
Hezbollah, as a Shia Muslim group, defeated a number of Sunni Muslim groups.
One of those Sunni groups, Hayat Tahrir al-Sham, has launched a strike at the regime that appears to have been lethal.
The group had based itself in Idlib, in the north of Syria, and apparently the regime saw it as more of an irritant than an existential threat.
Russia distracted
Whatever the group's fighting capability, it appears to have made an impeccable judgement in terms of timing. The outside forces that could have fended off any attack on the regime - Russia, Iran and Hezbollah - have all been seriously distracted.
Russia is focused almost entirely on its war in Ukraine. US president-elect Donald Trump has said he will seek a solution to the Ukraine-Russia war "within 24 hours" of taking office and he is almost certain to force the combatants to a table.
He is likely to use the financial leverage he has over Ukraine - through the US funding of Ukraine - to tell Ukrainian leader Volodymyr Zelenskyy that he must accept the current military reality or risk losing funding.
That would mean that Ukraine would be forced to give up the 20 per cent of its territory that Russia has taken since its invasion of Ukraine in February 2022.
With "the Trump factor" looming over that war, Ukraine made an audacious attack into Russia and took much of Kursk. It appears that Moscow is trying to regain Kursk so that it cannot be used by Ukraine in any negotiations - in other words, that Ukraine cannot say if you give us back Crimea (which Russia took from Ukraine in 2014) then we will return Kursk to you.
That was the thinking behind Russian leader Vladimir Putin arranging for an estimated 10,000 North Korean troops to arrive in Russia recently as part of an excepted Russia push to re-take Kursk.
Iran focused on Israel
It's not just Russia that has little capability to help Assad. Iran has its eyes on Israel rather than Syria.
When announcing that Israel had agreed to a ceasefire in Lebanon, Israeli Prime Minister Benjamin Netanyahu said Israel would focus on Iran.
Iran, therefore, is on alert for another possible attack by Israel. Furthermore, Iran's main proxy, Hezbollah, has been seriously wounded by Israel in the war in Lebanon.
Israel killed its all-powerful leader, Sheikh Hassan Nasrallah, several of its senior military commanders and many of its fighters.
So with Russia and Iran distracted and Hezbollah weak, the Hayat Tahrir al-Sham struck.
And what a strike it was. Rarely has any rebel group, in a single hit, changed the Middle East as comprehensively as this group has done.
But what comes next amid all these swirling currents of proxy powers and politics nobody can be sure.
- ABC