The streets of Damascus have seen the heaviest fighting since the begining of the Syrian uprising 17 months ago.
"This is the natural, expected development of the revolution and the fight for freedom in Syria .... And this revolution will continue, no matter what, even with all the strength the regime still has till now .... We still have a long way to go, we will not have high expectations about what's going on in Damascus but surely it's going to be the beginning of the end of this muderer regime."
- Akil Hashem, a former brigadier general of the Syrian army
Since Friday, the capital has seen gunfights and shelling. And according to reports, mortars and helicopter gunships have been used.
The fiercest fighting yet has been reported in various parts of the capital between rebel forces and government troops.
These are significant developments - but does it mean the conflict is reaching its final decisive phase?
UN chief Ban Ki-moon headed to China on Tuesday, on a mission to get support for tougher action on Syria.
His trip comes ahead of a UN Security Council vote this week on whether to allow sanctions and even military intervention in Syria if the al-Assad government fails to comply with a UN peace plan.
Also, the Security Council has to vote on the extension of a three-month mandate of a Syrian observer mission that expires on July 20.
Kofi Annan, the UN and Arab League special envoy, has been meeting Russian leaders in Moscow.
"The armed wing of the opposition has become much more organised and much more effective in the last few months .... And regardless of whether the rebels can sustain this fighting ... unfortunately it will be a bloodbath .... When the dust settles, psychologically, it [will] have shattering effects on the regime and its supporters, it empowers the opposition ... And it also sends multiple messages to Syrians who are fence-sitting that the Assad regime is no longer viable, the regime is vulnerable."
- Fawas Jerjes, a professor of Middle Eastern Politics and International Relations at London School of Economics
But the Russian foreign minister has made it clear there should be no foreign intervention in Syrian, saying that Syrians should come up with their own solution.
Rebels have announced a "Damascus volcano offensive" against the regime forces, witnesses heard heavy machine-gun fire in Sabaa Baherat square, which is in the heart of the city - where the Central Bank is located.
Activists are also reporting a build-up of tanks in the capital, with forces loyal to Bashar al-Assad blocking roads in and out of the city.
They are also said to have surrounded the Tadamon district, with snipers positioned on rooftops, ready to fire.
Another neighbourhood - near Tishreen Stadium - is also being shelled by the army. It is believed the military are using the sporting venue as a base.
There have also been reports heavy fighting in Kafer Souseh, which is further south.
And perhaps most significant is the violence in Midan - putting the rebels within striking distance of state security buildings, and not far from the historic old city.
But so far, all the fighting is still several kilometres from the presidential palace, and the country's largest air base, southwest of Damascus.
So is this the battle in Damascus or the battle for Damascus?
Inside Story, with presenter James Bays, discusses with guests: Mohamed Habash, a former member of the Syrian parliament; Akil Hashem, a former brigadier general of the Syrian army; and Fawas Jerjes, a professor of Middle Eastern Politics and International Relations at London School of Economics.
"This is my urgent message to all Mujahideen from all brigades to join their brothers the Mujahideen of Damascus who are defending the revolution. Those willing to join have to go ... through safe routes to Damascus. It is the moment of truth. It is the Damascus fight for salvation. It is either life, dignity and freedom or martyrdom and paradise."
Commander of Al-Emary Brigades, Captian Quais Quatana's statement for all Syrian Mujahideen
FIGHTING IN DAMASCUS
- Syria's military deployed armored vehicles near central Damascus
- Monitoring group: Fighting is the heaviest in the 17-month-long uprising
- Activists: Fighting in Damascus could be a turning point in the uprising
- Activists claim the army is losing control of some areas of Damascus
- Pro-government newspaper Al-Watan: “You will never take Damascus”
- Authorities vowed on Monday they would not surrender the capital
- Reports said the Syrian army had closed down the road to the airport
- Syrian observatory: Violence across Syria killed 105 people on Sunday
- UN Arab League envoy Kofi Annan is in Moscow for talks with top officials
- Russia is under strong diplomatic pressure to sign a UN resolution to end the Syrian conflict
- Russia and China still oppose move to threaten Damascus with sanctions
- Russian foreign minister Lavrov said al-Assad will not be forced from power
- International committee of the Red Cross: Conflict in Syria is a civil war