Former Ukrainian defence minister Mykhailo Fedorov has called for elections to be held despite the ongoing war with Russia, less than a month after his dismissal, he said in a video message posted online on Tuesday.

"Democracy must not be a hostage of Russia. We are fighting precisely because we want to be a free European state," Fedorov said in a video message. The state must find a "legal, safe and realistic mechanism" for holding a vote despite the continuing war, he said.

Fedorov was dismissed after less than six months as defence minister as part of a government reshuffle. Before that, he headed the Digital Transformation Ministry, which was newly created in 2019. His dismissal prompted demonstrations - mainly by young people - calling for his return to the defence portfolio.

On Tuesday, President Volodymyr Zelensky submitted the candidacy of acting Defence Minister Yevhenii Khmara for the post to parliament. Fedorov's video message is widely seen as a response to that nomination.

Fedorov's rising popularity was considered one of the reasons for his dismissal. At 35, he has also reached the minimum age required by the constitution to stand as a presidential candidate.

Under current martial law legislation, elections are prohibited. However, the law can be changed with a simple majority. Parliamentary elections, though, require a constitutional amendment - which is ruled out under the current martial law. Regular presidential, parliamentary and municipal elections have not taken place because of the war.

Ukraine has been defending itself against a full-scale Russian invasion for nearly four and a half years.