Throughout our coverage today we've been citing the Syrian Observatory for Human Rights, external, a UK-based human rights organisation.

Founded in 2006, the organisation works to monitor and publish developments within Syria with the aim of providing an "objective understanding" of events within the country.

Their website outlines their mission as to "preserve the truth in order to support justice, equality and freedom in Syria".

SOHR is not affiliated with any state, political party or organisation.

At least 16 civilians have been killed during strikes on a "gathering of people" at Aleppo's Al Basel roundabout on Saturday, according to the Syrian Observatory for Human Rights.

A further 20 were injured.

Al Basel square has emerged as a focal point in the incursion, with fighters earlier observed tearing down a Syrian flag in the square and toppling a statue of the late brother of President Bashar al-Assad, Basel al-Assad.

The UK-based monitoring group adds that it believes the strikes were carried out by Russian fighter jets.

Aleppo is currently under a curfew imposed by rebel forces that is effective until tomorrow. But we can now bring you a look at images from earlier today, after rebel forces moved into the city.

Photos show fighters celebrating their advances and setting a Syrian national flag alight.

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Image source, Getty Images

Al Basel Square become focal point of rebel incursionpublished at 16:22 Greenwich Mean Time

16:22 GMT

By Paul Brown

Since rebel fighters entered Aleppo yesterday evening, a lot of footage has been filmed around an area called "Al Basel Square” in the west of the city.

Yesterday fighters were seen tearing down the Syrian flag and earlier today we saw them toppling the statue of the late brother of President Bashar al-Assad, Basel al-Assad.

However, sharing videos of such a recognisable site may have been a security risk. In the last few hours footage has emerged from the area showing lifeless individuals on the ground, smoke rising and damage, following a reported air strike.

The Syrian army - which appears to have put up very little resistance to the rebel advance - has announced a "temporary troop withdrawal" from Aleppo, as it prepares for a counteroffensive.

Image source, Getty Images

Foreign ministers from Iran and Russia spoke by phone on Saturday, expressing their support for Syria against rebel forces that have taken Aleppo.

In a post on Telegram, Iran's Abbas Araghchi said the pair also spoke about the "need for coordination" between Russia, Iran and Turkey on this issue.

He adds that this is to help "neutralise this dangerous plot".

The Russian foreign ministry says that the sides discussed "serious concerns" about the developing situation in Syria and agreed to coordinate their response.

Rebels continue to make advances in Aleppo as curfew announcedpublished at 15:34 Greenwich Mean Time

15:34 GMT

Lina Sinjab
Middle East correspondent, reporting from Beirut

Image source, Getty Images

Throughout the day, we've seen rebel forces advancing and taking control over large parts of the city of Aleppo.

Government forces have also begun announcing that they have withdrawn and are saying that the rebels have taken control of one of Syria's largest cities.

This is really a very interesting time to see how this operation is taking place when President Assad's loyalists are weakened in the region - especially Iran and Hezbollah, whose fighters helped turned the tide of the Syrian civil war.

We are waiting to see the development - what's going to happen next?

Are the rebels going to hold control over Aleppo or will there be some sort of negotiations taking place?

All of this will hopefully be clarified in the days to come

The rebel forces announced a curfew starting at 17:00 local time (14:00 GMT) that will be in place until tomorrow.

This is also a time for them calculate their next steps.

Sebastian Usher

Islamist militant group Hayat Tahrir al-Sham (HTS) has a long and involved history in the Syrian conflict.

HTS was set up under a different name, Jabhat al-Nusra, in 2011 as a direct affiliate of Al Qaeda.

The IS group leader, Abu Bakr al-Baghdadi, was also involved in its formation.

It was regarded as one of the most effective and deadly of the groups ranged against President Assad.

But its jihadist ideology appeared to be its driving force rather than revolutionary zeal - and it was seen at the time as at odds with the main rebel coalition under the banner of Free Syria.

But in 2016, the group’s leader, Abu Mohammed al-Jawlani, publicly broke ranks with Al Qaeda, dissolved Jabhat al-Nusra and set up a new organisation, which took the name Hayat Tahrir al-Sham when it merged with several other similar groups a year later.

Sebastian Usher

Image source, Getty Images

The war in Syria has for the past four years felt as if it were effectively over.

President Bashar al-Assad’s rule is essentially uncontested in the country’s major cities, while some other parts of Syria remain out of his direct control.

These include Kurdish majority areas in the east, which have been more or less separate from Syrian state control since the early years of the conflict.

There has been some continued, though relatively muted unrest, in the south where the revolution against Assad’s rule began in 2011.

In the vast Syrian desert, holdouts from the group calling themselves Islamic State still pose a security threat, particularly during the truffle hunting season when people head to the area to find the highly profitable delicacy.

And in the north-west, the province of Idlib has been held by jihadist and rebel groups driven there at the height of the war.

The dominant force in Idlib is the one that has launched the surprise attack on Aleppo, which is the Islamist militant group Hayat Tahrir al-Sham - who I'll have more details about in my next post.

Aleppo is located in the northwest of Syria. It is the second largest city in the country.

We've mapped out where rebel forces have been sighted in relation to the city. These were the reported positions as of 09:00 GMT (12:00 local time).

As we've been reporting, Russia launched air strikes into Aleppo overnight for the first time since 2016, the Syrian Observatory for Human Rights (SOHR) says.

It comes as SOHR reports that rebel forces have taken control of "majority" of the city. The Syrian army says that the rebels have taken "large parts" of Aleppo - Syria's second-largest city.

The rebels' advancement into Aleppo is part of an offensive which began Wednesday. It is the largest offensive against the Syrian government to develop in years.

The rebels had been forced out of the city in 2016 by Syrian President Bashar al-Assad's army. This marks thefirst time since then that they have reached Aleppo.

Syria's military has said troops have been withdrawn temporarily in order to "prepare a counter-offensive".

A spokesperson from SOHR has told the BBC that city council, police stations and intelligence offices are standing "empty".

Image source, Reuters

Rebel forces in Syria have taken control of the "majority" of the country's second-largest city, Aleppo, according to the UK-based monitoring group Syrian Observatory for Human Rights (SOHR).

Russia has launched air strikes on parts of Aleppo in response - the first time since 2016.

More than 300 people have been killed since fighting intensified Wednesday, including 20 civilians, the observers said.

We'll be here throughout the afternoon to bring you the developing news lines and some further analysis. Stay with us - we'll have an overview of events with you shortly.