(NewsNation) — A group of civilians trapped for weeks inside a steel plant under Russian siege in Mariupol reached the southern Ukrainian town of Zaporizhzhia on Monday, after a renewed attempt to evacuated citizens of the besieged city was launched.

Video posted online 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.

About 100 of the estimated 1,000 people holed up inside the steel plant managed to escape.

An 80-year-old woman named Lidya shed tears as she was reunited with her granddaughter Monday.

The city’s evacuation now represents rare progress in the months-long war. It’s an area where Russian forces have inflicted some of the worst damage. Previous attempts to open safe corridors out of the port city on the Sea of Azov and other places had previously broken down.

Those 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.

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.

Elsewhere in the fight for Ukraine, Moscow released video Sunday claiming to show a high-precision missile it says hit a Ukrainian airfield, destroying targets.

But on Monday, U.S. defense officials said the Russian military is still struggling, calling it “tepid” and “anemic.”

Meanwhile, U.S. House Speaker Nancy Pelosi and other U.S. lawmakers visited Ukrainian President Volodymyr Zelenskyy to show American support against the invasion.

“We are visiting you to say thank you for your fight for freedom,” Pelosi said during a meeting with Ukrainian officials, according to a video posted to Zelenskyy’s official Telegram account on Sunday. “Your fight is a fight for everyone, and so our commitment is to be there for you until the fight is done.”

Zelenskyy said he was “very grateful for this powerful signal of support.”

Still, a defender of the steel plant said Russian forces resumed shelling the plant Sunday as soon as the civilians were evacuated. This comes as more than 100 civilians are expected to arrive in Zaporizhzhia on Monday.

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

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

As many as 100,000 people may still be in Mariupol, including an estimated 2,000 Ukrainian fighters beneath the sprawling, Soviet-era steel plant, the only part of the city not occupied by the Russians.

A siege of Mariupol since the early days of the war has trapped civilians with scarce access to food, water, medicine and electricity. A Russian airstrike hit a maternity hospital early in the conflict, and hundreds of people were reported killed when a theater was bombed.

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 steel plant urged groups like the U.N. and the Red Cross to also ensure the evacuation of wounded fighters at the plant, 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.

U.N. humanitarian spokesman Saviano Abreu said civilians arriving in Zaporizhzhia, about 140 miles northwest of Mariupol, would get immediate support, including psychological services. A Doctors Without Borders team was waiting for the U.N. convoy at a reception center for displaced people in the city.

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

More than 350,000 people have been evacuated from combat zones thanks to humanitarian corridors pre-agreed with Moscow, he said, adding the “organization of humanitarian corridors is one of the elements of the negotiation process which is ongoing.”

In Zaporizhzhia, residents ignored air raid sirens to visit cemeteries on Sunday, the Orthodox Christian day of the dead.

“If our dead could rise and see this, they would say, ‘It’s not possible, they’re worse than the Germans,’” Hennadiy Bondarenko, 61, said while marking the day with his family at a picnic table among the graves. “All our dead would join the fighting, including the Cossacks.”

Meanwhile, Russian forces embarked on a major military operation to seize the Donbas, Ukraine’s eastern industrial heartland, after failing to capture Kyiv.

A full picture of 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 airstrikes and artillery shelling.

The British Defense Ministry said in a daily briefing 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 committed over 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 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.

Hundreds of millions of dollars in military assistance has flowed into Ukraine during the war, but Russia’s vast armories mean Ukraine still needs massive support. Zelenskyy has appealed to the West for more weapons, and tougher economic sanctions on Russia.

European Union energy ministers are meeting 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.