People fleeing besieged Mariupol have described weeks of bombardments and deprivations as they arrived in Ukrainian-held territory.

It comes as relief workers await the first group of civilians freed from a steel plant that is the last redoubt of Ukrainian fighters in the devastated port city.

Video posted online on Sunday by Ukrainian forces showed elderly women and mothers with small children climbing over a steep pile of rubble from the sprawling Azovstal steel plant and eventually boarding a bus.

More than 100 civilians from the plant were expected to arrive in Zaporizhzhia, about 140 miles north-west of Mariupol, on Monday, Ukrainian President Volodymyr Zelensky said.

The evacuation, if successful, would represent rare progress in easing the human cost of the almost 10-week war, which has caused particular suffering in Mariupol.

Previous attempts to open safe corridors out of the city on the Sea of Azov and other places have broken down.

People fleeing Russian-occupied areas in the past have said their vehicles were fired on, and Ukrainian officials have repeatedly accused Russian forces of shelling agreed-upon evacuation routes.

“Today, for the first time in all the days of the war, this vitally needed green corridor has started working,” Mr Zelensky said on Sunday in a pre-recorded address published on his Telegram messaging channel.

At least some of the people evacuated from the plant were apparently taken to a village controlled by Moscow-backed separatists, though Russian state media reported they would be allowed to continue on to Ukrainian-held territory if they wanted to.

In the past, Ukrainian officials have accused Moscow’s troops of forcibly relocating civilians from areas they have captured to Russia; Moscow has said the people wanted to go to Russia.

While official evacuations have often faltered, many people have managed to flee Mariupol under their own steam in recent weeks.

Others are unable to escape.

“People without cars cannot leave. They’re desperate,” said Olena Gibert, who was among those arriving at a UN-backed reception centre in Zaporizhzhia in dusty and often damaged private cars.

“You need to go get them. People have nothing. We had nothing.”

She said many people still in Mariupol wish to escape the Russian-controlled city but cannot say so openly amid the atmosphere of constant pro-Russian propaganda.

A siege of the city since the early days of the war has trapped civilians in terrible conditions, with scarce access to food, water, medicine and electricity.

They have suffered intense bombardment, including a Russian air strike on a maternity hospital and the bombing of a theatre.

Anastasiia Dembytska, who took advantage of the brief ceasefire around the evacuation of civilians from the steel plant to leave with her daughter, nephew and dog, told the Associated Press (AP) her family survived by cooking on a makeshift stove and drinking well water.

She said she could see the steel plant from her window, when she dared to look out.

“We could see the rockets flying” and clouds of smoke over the plant, she said.

A defender of the plant said Russian forces resumed shelling the plant on Sunday as soon as some civilians there were evacuated.

Denys Shlega, commander of the 12th Operational Brigade of Ukraine’s National Guard, said in a televised interview that several hundred civilians remain trapped alongside nearly 500 wounded soldiers and “numerous” dead bodies.

“Several dozen small children are still in the bunkers underneath the plant,” Mr Shlega said.

It was unclear whether there would be further evacuation attempts.

Before the weekend evacuation, about 1,000 civilians were also believed to be in the sprawling, Soviet-era steel plant, along with an estimated 2,000 Ukrainian fighters.

As many as 100,000 people may still be in Mariupol overall.

The city, which had a pre-war population of more than 400,000, is a key Russian target because its capture would deprive Ukraine of a vital port, allow Moscow to establish a land corridor to the Crimean Peninsula, which it seized from Ukraine in 2014, and free up troops for fighting elsewhere in the Donbas, now Russia’s main focus.

A Ukrainian officer at the plant urged groups such as the UN and the Red Cross to ensure the evacuation of wounded fighters, though he acknowledged that reaching some of the injured is difficult.

“There’s rubble. We have no special equipment. It’s hard for soldiers to pick up slabs weighing tons only with their arms,” Sviatoslav Palamar, deputy commander of the Azov Regiment, told the AP in an interview.

“We hear voices of people who are still alive” inside shattered buildings.

The Azov Regiment originated as a far-right paramilitary unit and is now part of the Ukrainian military.

In his nightly address on Sunday, Mr Zelensky accused Moscow of waging “a war of extermination”, saying Russian shelling had hit food, grain and fertiliser warehouses, and residential neighbourhoods in the city of Kharkiv, in the Donbas and other regions.

After failing to capture Kyiv in the opening weeks of the war, Russian forces have embarked on a major military operation to seize the Donbas, Ukraine’s eastern industrial heartland where Moscow-backed separatists have been battling Ukrainian forces since 2014.

The Russian Defence Ministry said its forces struck dozens of military targets in eastern Ukraine in the past 24 hours, including concentrations of troops and weapons and an ammunition depot near Chervone in the Zaporizhzhia region.

The information could not be independently verified.

The Ukrainian president’s office said at least three people were killed and another three, including a child, were wounded in the eastern Luhansk region over the last 24 hours.

It said that four people were wounded in the shelling in Donetsk, another eastern region.

The regional administration in the Zaporizhzhia region farther west said that at least two people died and another four were wounded in the Russian shelling of the town of Orikhiv.

A full picture of the battle unfolding in eastern Ukraine is hard to capture.

The fighting makes it dangerous for reporters to move around, and both sides have introduced tight restrictions on reporting from the combat zone.

Western officials say Russia is advancing slowly in its eastern offensive and has captured some villages, but is inflicting heavy civilian casualties through indiscriminate bombing.

Ukrainian forces are fighting their offensive village-by-village while civilians flee air strikes and artillery shelling.

The British Ministry of Defence said in a daily briefing on Monday that it believes more than a quarter of all the fighting units Russia has deployed in Ukraine are now “combat ineffective” – unable to fight because of loss of troops or equipment.

The British military believes Russia has committed more than 120 so-called “battalion tactical groups” into the war since February, which represents 65% of all of Moscow’s combat strength.

Ukraine’s military claimed on Monday to have destroyed two small Russian patrol boats in the Black Sea.

Drone footage posted online showed what the Ukrainians described as two Russian Raptor boats exploding after being struck by missiles.

The AP could not immediately independently confirm the strikes.

Hundreds of millions of dollars in military assistance has flowed into Ukraine during the war, but Russia’s vast armouries mean Ukraine still needs massive support.

Mr Zelensky has appealed to the West for more weapons, and tougher economic sanctions on Russia.

US House Speaker Nancy Pelosi and other US legislators visited Mr Zelensky on Saturday to show American support.

European Union energy ministers were meeting on Monday to discuss a new set of sanctions, which could include restrictions on Russian oil – though Russia-dependent members of the 27-nation bloc including Hungary and Slovakia are wary of taking tough action.