Russian President Vladimir Putin on Tuesday said his country will achieve its goals of the military operation in Ukraine, while Ukrainian President Volodymyr Zelenskyy urged the European Union to impose sanctions on all Russian banks and Russian oil.

Putin described Russia's "special military operation" in Ukraine as a "noble" mission that would achieve its goals as Russian troops massed for a new offensive.

Ukrainian officials urged civilians to flee eastern areas ahead of the anticipated offensive, while the battle for the southern port city of Mariupol was reaching a decisive phase.

State television showed Putin visiting the Vostochny cosmodrome in Russia's Far East, accompanied by Belarusian President Alexander Lukashenko, to mark the anniversary of the Soviet Union's success in launching the first manned space flight.

Asked by Russian space agency workers if the operation in Ukraine would achieve its goals, Putin said: "Absolutely. I don't have any doubt at all."

Putin said Russia's main aims were to protect the Russian-speaking people of Donbas in eastern Ukraine and to end Ukraine's position as a center of nationalistic anti-Russian feeling.

The Russian president has cast what he calls a "special military operation" as a confrontation with the United States which he says is threatening Russia by meddling in its backyard, while the West says it is a brutal land grab of a sovereign country.

In Tuesday's remarks, he drew an analogy between Cosmonaut Yuri Gagarin's first space flight 61 years ago and Russia's defiance of Western economic sanctions today.

"The sanctions were total, the isolation was complete but the Soviet Union was still first in space," said Putin, 69, recalling his own wonderment as a schoolboy learning of the achievement.

"We don't intend to be isolated," Putin said. "It is impossible to severely isolate anyone in the modern world – especially such a vast country as Russia."

Lukashenko also dismissed the impact of sanctions: "Why on earth are we getting so worried about these sanctions?" he said.

He also has insisted that Belarus must be involved in negotiations to resolve the conflict in Ukraine and has said that Belarus had been unfairly labelled "an accomplice of the aggressor."

Meanwhile, Ukrainian President Volodymyr Zelenskyy on Tuesday urged the European Union to impose sanctions on all Russian banks and Russian oil and to set a deadline for ending imports of Russian gas.

"We cannot wait...We need powerful decisions, and the EU must take them now. They must sanction oil and all Russian banks...Each EU state must set terms for when they will refuse or limit (Russian) energy sources such as gas," he said.

Fighting in eastern Ukraine will intensify over the next two to three weeks, the UK's Defense Ministry said on Tuesday.

More than 4.5 million Ukrainian refugees have now fled their country, the United Nations refugee agency said – 90 percent of them women and children. The conflict has displaced more than 10 million people overall.

(With input from agencies)

(Cover: The combination of pictures shows Russian President Vladimir Putin (L) speaking during a press conference at Palazzo Chigi in Rome, July 4, 2019, and Ukrainian President Volodymyr Zelenskyy during a press conference at the Elysee presidential palace in Paris, June 17, 2019. /VCG)