Bombay Durpun - Dozens of civilians evacuated from Mariupol steel plant

The announcement came after the UN said a "safe passage operation" was ongoing at Azovstal, where Ukrainian forces say they and hundreds of civilians have been sheltering from Russian bombardment.

"Evacuation of civilians from Azovstal began," Zelensky said on Twitter.

Zelensky said the group was expected to arrive in the city of Zaporizhzhia, which is under Ukrainian control, on Monday.

"Grateful to our team! Now they, together with UN, are working on the evacuation of other civilians from the plant," he said.

The Russian defence ministry earlier said 46 civilians had left the plant on Saturday.

"All of the civilians were given accommodation, food and necessary medical help," the ministry said.

A ministry video showed a convoy of cars and buses travelling in the dark, marked with a "Z", the letter used by the Russian forces in the conflict.

- 'Barbaric' bombing -

The fate of Mariupol, a strategic port city linking Russian-held areas of southern and eastern Ukraine, has drawn worldwide condemnation.

Pope Francis on Sunday used his weekly Angelus prayer to renew his appeal for humanitarian corridors from the city, saying it had been "bombed and destroyed in a barbaric manner".

Thousands have been killed and millions displaced by Russia's invasion, which began on February 24.

Western powers have rushed to send military aid to Ukraine and imposed heavy sanctions on Russia.

"Do not be bullied by bullies," US Speaker of the House Nancy Pelosi told reporters at a press conference in Rzeszow in southern Poland on Sunday after returning from Ukraine.

"If they are making threats, you cannot back down. That's my view of it. We are here for the fight and you cannot fold to a bully," she said.

Pelosi met Zelensky on Saturday, becoming the most senior US figure to visit since the war began.

"We are visiting you to say thank you for your fight for freedom... Our commitment is to be there for you until the fight is done," she told him.

Pelosi also promised to enact the $33-billion (31-billion-euro) arms and support package announced by US President Joe Biden last week.

- Russian ruble introduced -

The conflict is concentrated in the east and south of Ukraine, although there have been Russian missile strikes across the country, mainly targeting infrastructure and supply lines.

Russia's defence ministry also on Sunday said it had used high-precision Onyx missiles to strike a hangar at a military aerodrome housing arms from the United States and European countries and destroyed the runway.

Ukrainian authorities had reported the strike on Saturday but said only that it destroyed the runway.

Russia has moved to solidify its grip on areas it controls and from Sunday introduced the Russian ruble in the region of Kherson -- initially to be used alongside the Ukrainian hryvnia.

"Beginning May 1, we will move to the ruble zone," Kirill Stremousov, a civilian and military administrator of Kherson, was cited as saying earlier by Russia's state news agency RIA Novosti.

He said there would be a period of four months in which the hryvnia could be used, but then "we will completely switch to settlements in rubles".

- 'Guard the line' -

On the front line in the east, Russian troops have advanced slowly but steadily in some areas -- helped by massive use of artillery -- but Ukrainian forces have also recaptured some territory in recent days, particularly around the city of Kharkiv.

One of the areas taken back from Russian control was the village of Ruska Lozova, which evacuees said had been occupied for two months.

"It was two months of terrible fear. Nothing else, a terrible and relentless fear," Natalia, a 28-year-old evacuee from Ruska Lozova, told AFP after reaching Kharkiv.

Kyiv has admitted that Russian forces have captured a string of villages in the Donbas region and has asked Western powers to deliver more heavy weapons to bolster its defences there.

"We cannot let the enemy move closer, we try to hold it with all our force."

R.Altobelli--BD