Explosions have sounded in Kyiv and the western city of Lviv, and the mayor of the Ukrainian capital said rescuers and medics were working at the site of a blast on the outskirts of the city.
Following attacks in the capital, mayor Vitali Klitschko urged Ukrainians not to return to Kyiv just yet in televised remarks on Saturday, warning that strikes were likely continue.
"We're not ruling out further strikes on the capital," Mr Klitschko said.
Russian media quoted its defence ministry as saying Russia had destroyed production buildings of an armoured vehicle plant in Kyiv and a military repair facility in the southern city of Mykolaiv.
The strikes were carried out by high-precision, long-range weapons, it said. Ukrainian officials said at least two civilians were killed and 18 wounded in Russian attacks across the country.
A diplomatic note revealed by US media warned Western powers of "unpredictable consequences" if they supplied Ukraine with advanced weaponry.
Ukraine Deputy Prime Minister Iryna Vereshchuk said nine humanitarian corridors had been agreed for Saturday (local time) to evacuate civilians, including from the besieged city of Mariupol by private cars.
Russia has denied targeting civilians since it invaded Ukraine on February 24 and has said Ukrainian and Western allegations of war crimes are fabricated.
Russia warns US, NATO against provision of arms to Ukraine
Russia has formally complained to the United States over its military aid to Ukraine, warning of "unpredictable consequences" if shipments of advanced weaponry go forward, US media reported.
In a diplomatic note this week, Moscow warned the United States and NATO against sending the "most sensitive" weapons for Kyiv to use in the conflict with Russia, saying such shipments were "adding fuel" to the situation and could come with "unpredictable consequences", the Washington Post reported.
The warning came the same week that US President Joe Biden pledged a new $US800 million ($1 billion) military aid package for Ukraine, including helicopters, howitzers and armoured personnel carriers.
The US State Department declined to comment on reports of the formal note.
"We won't confirm any private diplomatic correspondence," a spokesperson said.
"What we can confirm is that, along with allies and partners, we are providing Ukraine with billions of dollars worth of security assistance, which our Ukrainian partners are using to extraordinary effect to defend their country against Russia's unprovoked aggression and horrific acts of violence."
CNN also reported that one source familiar with the document said the complaint could mean Moscow is getting ready to adopt a more aggressive stance against the US and NATO as the invasion of Ukraine continues.
Mr Biden told his Ukrainian counterpart Volodymyr Zelenskyy of the new weapons aid package over the phone Wednesday, as Russia refocused its efforts eastward, the new frontline of the seven-week-old war.
"As Russia prepares to intensify its attack in the Donbas region, the United States will continue to provide Ukraine with the capabilities to defend itself," Mr Biden said.
"This new package of assistance will contain many of the highly effective weapons systems we have already provided and new capabilities tailored to the wider assault we expect Russia to launch in eastern Ukraine."
Mr Zelenskyy tweeted that he and Mr Biden had discussed the "additional package of defensive and possible macro-financial aid".
The new assistance included some of the heavier equipment that Washington had previously refused to provide to Kyiv for fear of escalating the conflict with nuclear-armed Russia.
'Reconciliation' the theme of Vatican Good Friday procession
The war in Ukraine loomed over the traditional Good Friday Colosseum procession in Rome, after the Vatican's choice of a Russian woman to share bearing the cross with a Ukrainian woman had angered Ukrainians.
In an apparent attempt to defuse the objections, when the moment arrived for the two women, who work together at a Rome hospital, to walk with the cross together, the ceremony's participants were invited to pause in "prayerful silence" and pray for peace.
The original script, written with the women's input, had spoken of prospects for "reconciliation".
That wording had sparked protests by both the Ukrainian ambassador to the Holy See and a Kyiv archbishop.
They objected to projecting what they saw as the idea of reconciliation while Ukraine is ravaged by war unleashed by Russia.
For the first time since before the pandemic, the solemn torchlit procession returned to the ancient arena in Rome.
The women were identified only by their first names in interviews on Italian Rai state TV: Irina, a nurse from Ukraine and Albina, a Russian nursing student.
Ahead of the procession, Albina told Rai that it was important to "pray for the children who are no more, for the soldiers who lost their lives and can't even be buried".
Irina described the sharing of the cross-carrying as a "great responsibility".
At the procession's conclusion, Pope Francis prayed that God "bring adversaries to shake hands, so that they taste reciprocal forgiveness".
While Francis has denounced the invasion and attacks on Ukraine as a "sacrilege", he has refrained from naming Russia as the aggressor, although his references to Russian President Vladimir Putin have been clear.
Francis dispatched his official almsgiver, Polish Cardinal Konrad Krajewski, to Kyiv to lead a Good Friday procession.
Italian Rai state TV showed the cardinal visiting Borodyanka, where he prayed over some of the bodies and leaned over to touch one, partially covered, body.
Russia issues travel ban on UK PM
Russia's foreign ministry said on Saturday it had barred entry to the country for British Prime Minister Boris Johnson, Foreign Secretary Liz Truss, Defence Secretary Ben Wallace and 10 other British government members and politicians.
The move was taken "in view of the unprecedented hostile action by the British Government, in particular the imposition of sanctions against senior Russian officials," the ministry said in a statement, adding that it would expand the list soon.
The Kremlin has described Mr Johnson, who has been one of Ukraine's staunchest backers, as "the most active participant in the race to be anti-Russian".
A week ago, Mr Johnson visited Kyiv where he and Ukrainian President Volodymyr Zelenskyy praised each other for their cooperation since the Russian invasion, which Moscow calls a "special operation".
"The UK and our international partners stand united in condemning the Russian government's reprehensible actions in Ukraine and calling for the Kremlin to stop the war," a British government spokesperson said in response to Moscow's decision to bar Mr Johnson and other British politicians.
"We remain resolute in our support for Ukraine," the spokesperson added.
ABC/wires
