Russian forces intensify shelling in Ukraine's Mariupol after breaking ceasefire, says mayor

The latest:

• UN says more than 350 civilians killed, more than 1.45 million have fled.

• Ukraine says evacuations halted, blames Russia for breaking ceasefire.

• Ukrainian President Volodymyr Zelenskysays forces holding key cities.

• ZelenskyasksU.S. for more planes while Putin warns against no-fly zones.

• Canadians urged to avoid all travel to Russia as Kremlin cracks down on media.

• MasterCard, Visa suspend Russian operationsin latest reaction to invasion.

Russian forces have intensified shelling in the port city of Mariupol, including with the use of airplanes, the mayor said Saturday night.

"The city is in a very, very difficult state of siege," Vadym Boychenko told Ukrainian TV. "Relentless shelling of residential blocks is ongoing, airplanes have been dropping bombs on residential areas."

The Russian Defence Ministry earlier said it had agreed on evacuation routes with Ukrainian forces for Mariupol, a strategic port in the southeast, and the eastern city of Volnovakha. The vaguely worded statement did not make clear how long the routes would remain open.

Boychenko said that thousands of children, women and the elderly came under fire as they arrived in the morning for a possible evacuation through a safe passage corridor. Evacuations were then halted.

"The Russian side is not holding to the ceasefire and has continued firing on Mariupol itself and on its surrounding area," said Kyrylo Tymoshenko, the deputy head of Ukraine President Volodymyr Zelensky's office. "Talks with the Russian Federation are ongoing regarding setting up a ceasefire and ensuring a safe humanitarian corridor."

Russia breached the deal in Volnovakha as well, Ukrainian Deputy Prime Minister Iryna Vereshchuk told reporters. "We appeal to the Russian side to stop firing," she said.

Meanwhile, Russian outlet RIA Novosti carried a Russian Defence Ministry claim that the firing came from inside both cities against Russian positions.

The struggle to enforce the ceasefire showed the fragility of efforts to stop fighting across Ukraine as people continued to flee the country on the 10th day after Russian forces invaded the country.

Russia has made significant advances in the south, clearly seeking to cut off Ukraine's access to the Azov Sea. Capturing Mariupol, which has been fending off the attack for six days, could allow Russia to build a land corridor to Crimea, which it annexed in 2014.

Powerful bombs dropped in Chernihiv

Russia dropped powerful bombs on residential areas of the city of Chernihiv, a regional official said Saturday.

Vyacheslav Chaus posted a photo of what he said was an undetonated FAB-500, a Soviet-designed 500-kilogramair-dropped bomb.

"Usually this weapon is used against military-industrial facilities and fortified structures," said Chaus, head of the region also namedChernihiv. "But in Chernihiv, against residential areas."

The city of Chernihiv, located north of Kyiv and with a population of 290,000, has come under heavy fire from Russian forces. Officials said 17 people in the region were killed in the shelling.

In a speech to Ukrainians on Saturday,Zelenskypointed to "the 500-kilogram bombs that were dropped on the houses of Ukrainians. Look at Borodyanka, at the destroyed schools, at the blown-up kindergartens. At the damaged Kharkiv Assumption Cathedral. Look what Russia has done."

Ukrainian forces holding key cities, president says

Zelensky said Ukrainian forces were holding key cities in the central and southeastern part of the country on Saturday, while the Russians were trying to block and keep encircled Kharkiv, Mykolaiv, Chernihiv and Sumy.

"We're inflicting losses on the occupants they could not see in their worst nightmare," Zelensky said.

He alleged that 10,000 Russian troops were killed in the 10 days of the war, a claim that could not be independently verified.

The Russian military doesn't offer regular updates on its casualties. Only once, on Wednesday, it revealed a death toll of nearly 500.

"This is horrible," Zelensky said. "Guys 18, 20 years old ... soldiers who weren't even explained what they were going to fight for."

Video released Saturday by the Ukrainian government showeda Russian military plane falling from the sky and crashing, as onlookers on the ground cheer.

Firefighters sprayed water on flames and smoke at a structure next to the debris of the plane, which bore a red star and the number 24.

Hundreds of civilians killed

The United Nations human rights office said it has confirmed the deaths of 351 civilians in Ukraine since the Russian invasion began on Feb. 24.

The Geneva-based office said that another 707 civilians were injured between Feb. 24 and midnight Friday.

The rights office uses strict methodology and only reports casualties it has confirmed.

It said on Saturday that it believes the real figures are considerably higher, "especially in government-controlled territory and especially in recent days," as the receipt of information from some places where there was intense fighting was delayed and many reports were still undergoing corroboration.

Ukrainian officials have presented far higher numbers.

Refugees flock to neighbouring countries

The International Organization for Migration (IOM) says the number of people who have left Ukraine since fighting began has now reached 1.45 million.

The UNmigration agency, citing figures from government ministries in countries where they have arrived, said Saturday that 787,300 of them went to Poland. Some 228,700 fled to Moldova, 144,700 to Hungary, 132,600 to Romania and 100,500 to Slovakia.

The IOM said that nationals of 138 countries have crossed Ukraine's borders into neighbouring nations.

UN Secretary General Antnio Guterressaid the UN is committed to scaling up its humanitarian operations to help both those who have stayed in Ukraine and those who've fled.

Guterres relayed the promise to Ukrainian Foreign Minister Dmytro Kuleba in a phone call on Saturday, UNspokespersonStephane Dujarric said.Dujarric said the two also discussed the conditions for safely evacuating civilians, including foreigners, from combat zones.

The UNhas predicted that the total number of refugees could swell to four million, to become the biggest such crisis this century.

The UN Security Council will hold a meeting on Monday afternoon on the escalating humanitarian needs that have arisen since Russia's invasion of Ukraine.

Canadians urged against travel to Russia

Meanwhile, the Canadian government on Saturdayissued an advisoryurging citizens to avoid all travel to Russia, adding that for those already in the country, "you should leave while commercial means are still available."

The advisory comes a day after the CBCjoined other international media outlets in temporarily suspendingall of itsreporting from the ground in Russia in response to a new lawsetting out prison sentences of up to 15 years for spreading what the Kremlin deemed to be fake information about its armed forces.

WATCH |Kremlin tightens grip on media access:

Kremlin tightens grip on Russians' access to media with misinformation law

3 years ago

Duration 1:54

President Vladimir Putin is tightening his grip on media and information in Russia, signing into power a new law that could see journalists sentenced to 15 years in prison for straying from the country's approved narrative on what is happening in Ukraine.

Kremlin spokespersonDmitry Peskovdefended the law on Saturday, telling reporters that the measure was justified on the grounds of an "information war which was unleashed against our country."Asked how Russians could express opinions thatdon't match the official government position, Peskov said, "Within the bounds of the law."

The passing of the law comes amid a broader crackdown on media outlets and social media in Russia. Facebook and Twitter were both blocked in Russia on Friday.