What's happening in Aleppo?
- 28 November 2016
- From the section Middle East
The northern Syrian city of Aleppo has been caught in a four-year deadlock - but that has now been broken.
Aleppo has become a key battleground in the war between forces loyal to President Bashar al-Assad and Western-backed rebels who want to overthrow him.
Troops have now recaptured a number of besieged, rebel-held eastern areas. They had help, from Iranian-backed Shia militias and Russian air strikes.
But inside those areas are tens of thousands of people suffering serious food and fuel shortages.
Why is Aleppo important?
Aleppo was once Syria's largest city, with a population of about 2.3 million. It was also the country's industrial and financial centre.
The old city was a Unesco World Heritage site, and was famous for its 13th Century citadel, 12th Century Great Mosque and huge covered markets, or souks.
When the uprising against President Assad erupted in 2011, Aleppo didn't see the large protests or the deadly violence that shook other towns and cities.
But it suddenly became a battleground in July 2012.
Rebel fighters launched an offensive to kick out government forces and gain control over northern Syria.
The rebel offensive wasn't decisive though.
Aleppo ended up divided roughly in half - the opposition ended up controlling the east, and the government the west.
Over the next four years, the battle for Aleppo became a microcosm of the wider conflict in Syria.
It highlighted the weakness of both sides, as well as the failure of the international community to protect civilians and broker a peace agreement.
- Why Assad wants to take all of Aleppo
- Why is Russia engaged in Aleppo?
- Profile: Aleppo, Syria's second city
How was the deadlock broken?
At the start of the year, eastern Aleppo was linked to the border with Turkey via rebel-held territory to the north and west.
Turkey's government is a key backer of the rebellion against Mr Assad.
In early February, government forces cut the main supply route after breaking a long-standing siege of two towns in the Aleppo countryside, Nubul and Zahraa.
Troops and militiamen continued to advance over the next few months. In July, they took control of the strategically-important Castello Road in northern Aleppo, the only route into the rebel-held east.
Deliveries of food and medicine by the UN stopped and about 275,000 people suddenly found themselves under siege.
In August, rebels and al-Qaeda-linked jihadist fighters in the countryside outside Aleppo broke through to the east, briefly establishing a corridor through one district in the south, Ramousseh.
But government forces retook the area in early September and resumed the siege.
They launched an all-out assault later that month. It was an aerial bombardment of unprecedented scale and intensity, that reportedly included bunker-busting, incendiary and cluster munitions.
The government and Russia declared a pause in the air strikes on mid-October to allow civilians and rebels to leave the east, but very few people took up the offer.
On 15 November, the government air campaign resumed and troops stepped up their ground offensive. By the end of the month, they had pushed into several northern districts and forced rebels and jihadists to retreat southwards. Thousands of people fled their homes.
Food and fuel are running out, and basic infrastructure and health care have been obliterated - at one point in November, all hospitals in eastern Aleppo were virtually out of action as a result of air strikes.
The UN says hundreds of civilians have died, but the government and Russia have denied targeting them. Rebel rocket and mortar fire has also killed dozens of people in the government-controlled west.
- Life under siege in rebel-held Aleppo
- Why are people still living in east Aleppo?
- Why are Aleppo's children so badly affected?
What happens if rebel-held Aleppo falls?
The UN's special envoy to Syria, Staffan de Mistura, warned in October that the east could be "totally destroyed" by Christmas, leaving thousands of civilians dead.
In late November, Mr de Mistura told a group of German politicians that he was very concerned about President Assad "taking over in a brutal, aggressive way" and drew parallels to the siege of the Croatian town of Vukovar in 1991.
If rebel-held Aleppo is retaken, Syria's government will control the country's four largest cities.
President Assad may hope that the gains made in Aleppo will snowball into something more and help bring the civil war to an end.
But with rebel forces, jihadist groups and Kurds still controlling large parts of the country, there would still be a long way to go.