LISBON: Ukraine's first lady Olena Zelenska said on Wednesday her war-torn country will be in trouble if the world's solidarity starts to fade, but added she still believes humanity will prevail and support will continue.

A cost-of-living crisis, including soaring energy bills, is topping Europe's political agenda and some fear this is slowly diverting attention away from the conflict shattering Ukraine since Russian forces invaded in February.

"I don't want to believe that support (for Ukraine) is fading. I believe it won't diminish," Zelenska told Reuters in an interview on the sidelines of Europe's largest tech event, Lisbon's Web Summit.

"I believe common sense, empathy, human emotions and relations will win," she added, urging people to think about the world they want to live in the future.

"If that's wrong, we are in trouble."

Russian forces swept into Ukraine on Feb. 24 in a conflict that has since killed thousands of people, displaced more than eight million, laid waste to cities and towns and reopened Cold War-era divisions.

Russia calls the conflict a "special military operation" to eliminate dangerous nationalists and protect Russian speakers in its fellow former Soviet republic. Kyiv calls Moscow's invasion an unprovoked imperialist land grab.

"If someone thinks that aggression can be justified...this person is under the influence of propaganda," Zelenska said.

Since the start of the invasion, the wife of Ukrainian President Volodymyr Zelenskiy has used her role to help maintain diplomatic relations with world leaders and raise awareness of the human cost of the war.

She said there were no textbooks "that could teach you how to be a president's wife", particularly during a war.

"I can't say I wanted to be the centre of attention but every voice in this information war is important. If I'm heard, I will use this opportunity."

The European Union last month gave its final approval for a new batch of sanctions against Russia that are meant to ultimately undermine Moscow's reserves and its resolve to continue the war.

Asked what will it take to stop Russia, Zelenska said sanctions "can't be stopped and only have to be strengthened".

"We would like Western countries to continue on this path," she said. "The more the financial pressure and sanctions are put on the aggressor, the less opportunities they will have to wage a war against Ukraine.

"We hope this will work."