As separatists in Crimea kept up pressure for unification with Moscow, Ukraine on Sunday solemnly commemorated the 200th anniversary of the birth of its greatest poet, with the prime minister vowing not to give up "a single centimetre" of Ukrainian territory.
"This is our land," Arseniy Yatsenyuk told a crowd gathered at the Kyiv statue to writer and nationalist Taras Shevchenko. "Our fathers and grandfathers have spilled their blood for this land. And we won't budge a single centimetre from Ukrainian land. Let Russia and its president know this."
"We're one country, one family and we're here together with our kobzar (bard) Taras," said acting President Oleksandr Turchynov.
In the afternoon, Ukrainians in the tens of thousands massed in their capital city's downtown for a multi-faith prayer meeting to show their unity and honour Shevchenko, a son of peasant serfs who is considered the father of modern Ukrainian literature and is a national hero.
One of the speakers, former imprisoned Russian tycoon Mikhail Khodorkovsky, almost burst into tears as he implored the crowd to believe that not all Russians support their country's recent actions in Ukraine.
"I want you to know there is a completely different Russia," Khodorkovsky said.
But in Moscow, Russian President Vladimir Putin made it clear that he supports the March 16 referendum the regional parliament in Crimea plans to hold on leaving Ukraine to join Russia.
In phone calls with German Chancellor Angela Merkel and British Minister David Cameron on Sunday, Putin defended the situation in Crimea, where Russia reinforced its armed presence this weekend, the Kremlin said.
"The steps taken by the legitimate leadership of Crimea are based on the norms of international law and aim to ensure the legal interests of the population of the peninsula," said Putin, according to the Kremlin.
Following an extraordinary meeting of the Ukrainian government in Kyiv on Sunday, Yatsenyuk announced that he will fly to the United States this week for high-level talks on "resolution of the situation in Ukraine," the Interfax news agency reported.
"Our country and our people are facing the biggest challenges in the history of modern independent Ukraine," the prime minister said earlier in the day. "Will we be able to deal with these challenges? There should only be one answer to this question and that is: yes."
Crimea, a strategic peninsula in southern Ukraine, has become the flashpoint in the battle for Ukraine, where three months of protests sparked by President Victor Yanukovych's decision to ditch a significant treaty with the 28-nation European Union after strong pressure from Russia led to his downfall. A majority of people in Crimea identify with Russia, and Moscow's Black Sea Fleet is based in Sevastopol, as is Ukraine's.
This weekend, Russian Foreign Minister Sergey Lavrov ruled out any dialogue with Ukraine's new authorities, whom he dismissed as the puppets of extremists.
Senior lawmakers in Moscow have said they will support Ukraine's March 16 referendum, ignoring sanctions threats and warnings from President Barack Obama that the vote would violate international law.