Some 130 people have been rescued so far from a theater in the besieged city of Mariupol that was hit by a Russian air strike, but "hundreds" more are still trapped under the rubble, Ukrainian President Volodymyr Zelenskiy said, as Mariupol's mayor said that fighting for the strategic Black Sea port has reached the city center.
Some 350,000 people remain trapped inside the city in horrific conditions, aid workers say.
Meanwhile, Russian forces have pressed ahead with their relentless and indiscriminate bombardment Ukrainian cities despite international calls for an immediate cease-fire.
Russian President Vladimir Putin, despite an appeal by German Chancellor Olaf Scholz to halt the unprovoked invasion of Ukraine, made a defiant appearance before a huge crowd at a state-organized concert in a Moscow stadium, using the venue to justify the invasion of Ukraine. Reports say many public-sector workers were coerced into attending the event.
SEE ALSO: Russian State TV Cuts Putin's Speech Mid-Sentence, Kremlin Blames Technical IssueU.S. President Joe Biden outlined to his Chinese counterpart Xi Jinping the "consequences" of any support for Russia in its war against neighboring Ukraine, the White House said on March 18.
China has repeatedly refused to condemn Russia, and Washington fears Beijing could now deliver financial and military support for Moscow.
SEE ALSO: Biden Warns Xi About 'Consequences' Of Chinese Support For Russia's Ukraine WarZelenskiy said in a video posted on Facebook on March 18 that rescue operations at the site of the Mariupol theater would continue even though Russian forces continue to shell the besieged port city. "Hundreds of Mariupol residents are still beneath the rubble," he said.
The theater was being used as a shelter for hundreds of residents trapped inside the city when Russian shells destroyed it on March 16.
Officials have yet to say how many people, if any, died in the attack. They have said that most were under the theater inside a bomb shelter, which survived the blasts intact.
The attack on a civilian building marked with the words "children" in Russian, which was clearly visible from the air, has sparked a wave of international revulsion and heaped pressure on Russia's few remaining allies -- most notably China -- to condemn Moscow's deliberate targeting of nonmilitary sites during the war, which began on February 24.
The word "children" is written in large white letters in Russian in satellite images of the Mariupol theater taken on March 14.
Mariupol Mayor Vadym Boichenko told the BBC that fighting for the strategic Black Sea port had reached the city center.
WATCH: A hospital in Ukraine's besieged southeastern port city of Mariupol is overflowing with patients. With Russian forces having destroyed all the other medical facilities in the city, it serves as an emergency department, a maternity ward, and a morgue.
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Bodies Litter The Floors Of Mariupol Hospital As Ukrainian Medics Fight To Save Lives
In a phone call on March 18, French President Emmanuel Macron told Putin, that he was "extremely concerned" about the situation in Mariupol, the French presidential office said on March 18. The call lasted just over one hour, it added.
The Kremlin said that during the call Putin accused Kyiv of "war crimes," saying that Moscow was doing "everything possible" to avoid civilian deaths in Ukraine, despite overwhelming evidence documented by Western journalists of Russian forces' indiscriminate attacks on civilian targets.
"Attention was drawn to the numerous war crimes committed daily by the Ukrainian security forces, in particular massive rocket and artillery attacks on the cities of the Donbas [under the control of Moscow-backed separatists]," the Kremlin said of the call.
Putin told Macron the Russian Army was "doing everything possible to safeguard the lives of peaceful civilians, including by organizing humanitarian corridors for their safe evacuation," the Kremlin added.
Earlier, Germany's Scholz and Putin spoke for almost an hour on the "ongoing war in Ukraine and efforts to end it," Scholz's office said in a statement on March 18.
It gave no further details, but the Kremlin said in a separate statement that "the Russian side is ready to continue the search for solutions in line with its well-known principled approaches."
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Moscow's unprovoked attack on Ukraine has seen more than 187,000 people flee to Germany, according to the Interior Ministry, though experts say the number is probably much higher as many of the 2 million who have entered Poland likely continued on to Germany.
On the ground, missiles struck a maintenance facility near Lviv's international airport, while the Polish Border Guard service reported that more than 2 million refugees had entered Poland since Russia launched its invasion of Ukraine more than three weeks ago.
Ukrainian Foreign Minister Dmytro Kuleba said the EU foreign policy chief Josep Borrell discussed protection and help for Ukrainians who have fled.
Kuleba said on Twitter that he and Borrell also discussed a fifth set of EU sanctions against Russia over its unprovoked invasion.
The mayor of the western Ukrainian city of Lviv said earlier on March 18 that Russian rockets struck an airport maintenance plant near the city's airport on March 18 as Japan and Australia slapped fresh sanctions on Russian entities and U.S. President Joe Biden prepared to speak with Chinese President Xi Jinping over Beijing's position on Moscow's unprovoked invasion of Ukraine.
Lviv Mayor Andriy Sadoviy said on March 18 that several missiles hit the facility for repairing military aircraft, sending a plume of smoke into the air. The strike also damaged a bus repair facility. No casualties were immediately reported.
Russian forces pressed their assault on other Ukrainian cities, including Kyiv, where shelling was reported in the suburbs. Early morning barrages hit a residential building in the Podil neighborhood, killing at least one person, according to emergency services.
There are also reports of mass casualties following a missile attack on a Ukrainian Army barracks in the southern city of Mykolayiv, with one account saying at least 45 people have died.
The missiles that hit Lviv were launched from the Black Sea, the Ukrainian Air Force's western command said on Facebook, adding that two of the six missiles launched were shot down.
Across Ukraine, hospitals, schools, residential areas, and buildings in which people have sought safety have been attacked, prompting world leaders to push for an investigation.
The UN said at least 816 civilians had been killed and 1,333 wounded in Ukraine through to March 17.
Most of the casualties were from explosive weapons such as shelling from heavy artillery and multiple-launch rocket systems, and missile and air strikes, according to the UN human rights office.
The actual toll is likely a lot higher, it said, since it has been unable to collect information from some of the worst-hit cities, including Mariupol.
Earlier on March 18, Japan and Australia announced separate measures sanctioning Russian individuals and organizations as punishment for the invasion of Ukraine.
Japan will impose sanctions against 15 Russian individuals and nine organizations, including defense officials and state-owned arms exporter Rosoboroneksport, while Australia will target two Russian billionaires -- Oleg Deripaska and Viktor Vekselberg -- with links to its mining industry.
SEE ALSO: Where Are The Blue Helmets? Why The UN Can't Keep The Peace In Ukraine Also on March 18, Pope Francis called the war in Ukraine a "perverse abuse of power" that has condemned defenseless people to violence."The tragedy of the war taking place in the heart of Europe has left us stunned," he said.
The pope has not named Russia in any of his condemnations but he has used phrases such as "unacceptable armed aggression."
His latest condemnation came in a message to a Catholic Church conference in Bratislava, the capital of Slovakia, which has opened its doors to refugees.