By Natalia Zinets
(Reuters) - Ukraine proposed talks with Moscow over evacuating troops and civilians from Mariupol after a Russian surrender-or-die ultimatum expired on Wednesday, leaving many trapped at a steel plant, the last main stronghold of resistance.
A few dozen civilians managed to leave the strategically important southeastern port in a small bus convoy, according to Reuters witnesses, escaping the fiercest battle of the nearly eight-week-long war.
A Ukrainian marine commander, Serhiy Volny, said fighters there may not be able to hold out for much longer. President Volodymyr Zelenskiy has said an estimated 1,000 civilians are also sheltering at the steel works.
Ukraine is ready for a "special round of negotiations" with no conditions "to save our guys, (the far right) Azov (battalion), military, civilians, children, the living and the wounded," negotiator Mykhailo Podolyak tweeted.
Fighters remain holed up in the plant and have ignored an ultimatum by Russia to surrender. David Arakhamia, a second negotiator, said in an online post that he and Podolyak were in constant contact with Ukrainian forces in the city.
"Today, in a conversation with the city defenders, a proposal was put forward to hold direct negotiations, on site, on the evacuation of our military garrison," he said. "For our part, we are ready to arrive for such negotiations at any time as soon as we receive confirmation from the Russian side."
Fewer civilians than hoped left on Wednesday, according to the authorities.
Over five million Ukrainians have fled abroad since Russia invaded on Feb. 24, the biggest attack on a European state since 1945. Russia has yet to capture any major cities.
Ukraine said it had so far held off an assault by thousands of Russian troops attempting to advance in what Kyiv calls the Battle of the Donbas, a new campaign to seize two eastern provinces Moscow claims on behalf of separatists.
Russia's forces had carried out strikes on dozens of military facilities in eastern Ukraine and had shot down a Ukrainian Mi-8 helicopter near the village of Koroviy Yar, its defence ministry said.
On Wednesday, Russia conducted a first test launch of its Sarmat intercontinental ballistic missile, a new and long-awaited addition to its nuclear arsenal.
"This truly unique weapon will ... provide food for thought for those who, in the heat of frenzied aggressive rhetoric, try to threaten our country," President Vladimir Putin said.
Russia calls its incursion a "special military operation" to demilitarise and "denazify" Ukraine. Kyiv and its Western allies reject that as a false pretext.
The West has responded with a slew of sanctions.
The United States on Wednesday imposed restrictions on dozens of people and entities, including a commercial bank and a virtual currency mining company, targeting the evasion of existing rules.
BILLOWING CLOUDS OF SMOKE
Mariupol, once a prosperous city of 400,000, is now a wasteland where corpses lie in the streets and Russia was hitting the Azovstal steel plant with bunker-buster bombs, the government in Kyiv said.
Large black clouds of smoke billowed from there on Wednesday as evacuees queued to get onto buses, some clutching luggage or carrying small pets in their arms.
Pensioner Tamara, 64, said she was going to stay with her sister in Zaporizhzhia. She was leaving the city with her husband, daughter, son-in-law and grandson.
"It is a pleasure ... to leave after this nightmare. We lived in basements for 30 days," she said tearfully.
Ukraine's Deputy Prime Minister Iryna Vereshchuk accused Russian forces of failing to observe a local ceasefire agreement long enough to allow large numbers of people to leave.
Russia did not immediately respond to the allegation.
It denies targeting civilians and has blamed Ukraine for the failure of earlier attempts to organise humanitarian corridors out of Mariupol.
The deputy commander of the Azov Regiment in Mariupol, Svyatoslav Kalamar, said several bunkers under the plant still held about 80-100 civilians each.
Just five people in Mariupol had surrendered following Moscow's 2 p.m. (1100 GMT) surrender-or-die ultimatum, Russian-backed separatists said.
Ukraine has proposed swapping Russian prisoners of war in exchange for safe passage for trapped civilians and soldiers.
If Russia captured Mariupol it would link territory held by pro-Russian separatists in the east with the Crimea region that Moscow annexed in 2014.
Moscow was forced to retreat from northern Ukraine after an assault on Kyiv was repelled last month, but has poured troops back in for an assault on the east that began this week.
Putin says Ukraine mistreated Russian speakers in the Donbas, an accusation Kyiv dismisses as false.
Russia was focusing on advancing towards the strategically important Donbas city of Sloviansk, but "so far they are not succeeding", Ukrainian presidential advisor Oleksiy Arestovych said.
PEACE TALKS ELUSIVE
Meanwhile, peace negotiations have stalled.
The Kremlin accused Kyiv on Wednesday of delaying the talks and changing its positions. Kyiv accuses Moscow of blocking talks by refusing humanitarian ceasefires.
The head of Ukraine's Orthodox Church asked clergy and the faithful to forgo services on Easter Saturday night in areas affected by fighting, fearing the Russian bombardments will continue without respite.
U.S. President Joe Biden was convening top U.S. military leaders on Wednesday in an annual White House gathering that takes on special significance as the war in Ukraine enters a new phase and Washington plans more military aid.
Charles Michel, head of the European Council that groups the 27 EU member states, met Zelenskiy in Kyiv in a show of solidarity.
(Reporting by Natalia Zinets in Ukraine and Reuters journalists; Writing by Peter Graff, Gareth Jones and Costas Pitas; Editing by Philippa Fletcher, Tomasz Janowski and Grant McCool)