A maternity hospital shelled by Russian soldiers. Families bombed as they sheltered in an historic theatre.
Tens of thousands of people running out of food and water.
The siege of Mariupol has been one of the worst humanitarian catastrophes in Ukraine after Russia invaded the country on February 24.
Ukrainian officials say at least 20,000 civilians were killed there by Russian forces employing tactics of mass destruction used in earlier campaigns in Syria and Chechnya.
"Mariupol has been destroyed, there are tens of thousands of dead, but even despite this, the Russians are not stopping their offensive," Ukrainian President Volodymyr Zelenskyy said in a video address this week.
It has become the site of some of the war's most brutal assaults and alleged war crimes.
If Russia has truly captured Mariupol as it says it has, it would be the first major city to fall since the invasion began.
Why does Russia want Mariupol?
Located in south-eastern Ukraine — less than 60 kilometres from the Russian border — Mariupol has been under siege for almost two months.
Home to more than 400,000 people before the war, it is the biggest Ukrainian city on the Sea of Azov and the main port serving the industries and agriculture of eastern Ukraine.
It is also the site of some of Ukraine's biggest metals plants.
Control of Mariupol would provide a strategically important path between Crimea and the pro-Russian Donetsk and Luhansk regions — all territories now controlled by Moscow.
It would unite Russian forces on two of the main axes of the invasion, and free them up to join an expected new offensive against the main Ukrainian force in the east.
Has it been captured?
Street battles are ongoing in Mariupol as Ukraine tries to break Russia's siege of the city, according to Ukraine's defence ministry spokesman Oleksandr Motuzyanyk.
"The situation in Mariupol is difficult and hard. Fighting is happening right now. The Russian army is constantly calling on additional units to storm the city," he said.
He said for the first time since the start of its invasion, Russia used long-range bombers to attack the port city on Friday (local time).
Moscow says it hopes to seize all of Mariupol soon.
Russia's defence ministry said it had captured the Ilyich steel works in Mariupol, but the report could not be confirmed and Mr Motuzyanyk said active fighting was taking place around the factory.
Ukrainian defenders are mainly believed to be holding out in Azovstal, another huge steel works.
Both plants are owned by Metinvest — the empire of Ukraine's richest businessman and backbone of Ukraine's industrial east — which said it would never let its enterprises operate under Russian occupation.
Earlier this week, Russia claimed it had captured the city's port and that more than 1,000 Ukrainian marines had surrendered, although Ukraine has not confirmed that.
An assessment by the US-based Institute for the Study of War said while Russia had continued to gain ground in Mariupol, "Russian claims of a mass Ukrainian surrender are likely false".
Earlier in the week, a post on the Ukrainian Marine Brigade's Facebook page said the unit was preparing for its final battle in Mariupol, as its troops had run out of ammunition.
"Today will probably be the ultimate battle, as there is no ammo left," said the post on Monday (local time).
"Beyond that: hand-to-hand fighting. Beyond that, for some death, for others capture."
Some Ukrainian officials said the post may have been fake, and that troops were still holding out.
Prominent among the Ukrainian forces that have defended Mariupol is the Azov Regiment, a militia with far-right origins incorporated into Ukraine's national guard.
Russia has portrayed destroying that group as one of its main war aims.
Claiming its first big prize in eastern Ukraine could also give Russia a stronger position to negotiate at any peace talks.
Bodies 'carpeted through the streets'
Ukrainian officials have said around a third of Mariupol's population escaped before the siege, a similar number got out during it, while around 120,000 were trapped inside.
They sheltered for weeks in cellars with no power or heat, or access to outside shipments of food, water or medicine.
Daily attempts to send convoys to bring in aid and evacuate civilians failed throughout the siege, with Ukraine blaming Russia for looting shipments and refusing to let buses pass through the blockade.
Moscow said Ukraine was to blame for failing to observe ceasefires.
Ukraine's Deputy Prime Minister, Iryna Vereshchuk, said nine humanitarian corridors had been agreed for Friday (local time) to evacuate civilians, including by private car from Mariupol.
Bodies have been buried in mass graves or makeshift graves in gardens.
Mariupol mayor Vadym Boychenko told the Associated Press that dead bodies were "carpeted through the streets".
He said Russian forces had brought mobile cremation equipment to Mariupol to dispose of the corpses.
"Mobile crematoriums have arrived in the form of trucks: You open it, and there is a pipe inside and these bodies are burned," Mr Boychenko said.
International organisations such as the Red Cross and the United Nations say they believe thousands have died but the extent of suffering cannot be assessed yet because the city has been cut off.
Accusations of war crimes
Among the major incidents that drew international outcry was the bombing of the Mariupol Maternity House and Children's Hospital on March 9, when wounded pregnant women were photographed being carried out of rubble.
Several people died and at least 17 others, including women in labour, were injured.
"A children's hospital. A maternity hospital. How did they threaten the Russian Federation?" Mr Zelenskyy said in an address last month.
Ukrainian blogger Mariana Vishegirskaya gave birth to a girl the day after the air strike.
"We were laying in wards when glasses, frames, windows and walls flew apart," Ms Vishegirskaya said at the time.
"We don't know how it happened. We were in our wards and some had time to cover themselves, some didn't."
A week later, Mariupol's Drama Theatre was destroyed during an attack in which local Ukrainian officials said roughly 300 people were killed.
The word "children" had been spelled out on the street in front of the building, visible from space.
The theatre was among 20 cultural sites verified by UNESCO to have been damaged by fighting in Mariupol and the surrounding Donetsk region.
Russia denies targeting civilians in Mariupol and has claimed, without presenting evidence, that incidents including the theatre bombing and maternity hospital attack were staged.
The Ukrainian government and its Western allies dismiss this as a smear to deflect blame.
A mission of experts set up by Organization for Security and Cooperation in Europe (OSCE) nations this week said it had found evidence of war crimes and crimes against humanity by Russia in Ukraine.
Russia's mission to the OSCE said on Twitter the report "is based solely on unfounded propaganda theses, contains references to dubious sources and logical stretches in the style of 'highly likely'".
Despite Russian denials, the report said the maternity hospital attack was carried out by Russia and those responsible had committed a war crime.
It also said the strike on the theatre, which killed hundreds of civilians was a war crime.
The mission also found what it called violations by Ukraine, particularly in its treatment of prisoners of war, but it said Russia's violations "are by far larger in nature and scale".
"Taken as a whole, the report documents the catalog of inhumanity perpetrated by Russia's forces in Ukraine," US ambassador to the OSCE Michael Carpenter said in a statement.
"This includes evidence of direct targeting of civilians, attacks on medical facilities, rape, executions, looting, and forced deportation of civilians to Russia."
Ukraine says Russia has forcibly moved thousands of Mariupol residents to Russia, including some unaccompanied children it views as having been kidnapped.
Citing figures from Mariupol's city administration, Ukraine's human rights ombudsman Lyudmyla Denisova said 33,000 Ukrainians had been deported to Russia or territories held by Russian-backed separatists in eastern Ukraine.
Moscow denies this and says it has taken in refugees, claiming last Sunday it had "evacuated" 723,000 people from Ukraine since the start of what it called its "special operation".
ABC/wires
