Protests have been taking place in several Ukrainian cities against President Volodymyr Zelensky's surprise dismissal of popular Defence Minister Mykhailo Fedorov.

A crowd of people - mostly young - gathered in Kyiv, holding up signs reading "Hands off Fedorov" and "Stop sabotaging victory!" and chanting "Shame!".

Zelensky has not yet explained his decision, which is causing significant upset among commentators and the military as well as parts of civil society.

Fedorov, 35, was appointed only in January but has been credited with energising the ministry, heading a drive against corruption and using data to analyse and try to improve performance on the front line.

MPs were due to vote later on Thursday on the proposed replacement as defence minister, Ihor Klymenko, who currently heads the interior ministry.

Some in Ukraine have linked Fedorov's dismissal to tensions between him and the more conventionally minded Commander-in-Chief Oleksandr Syrskyi, while others have highlighted his failure to move swiftly enough on overhauling mobilisation in the military.

"This is the worst mistake Zelensky has made during his entire presidency," Oleksandr, a Ukrainian soldier, told the BBC.

He had signed up to the army earlier this year because he trusted Fedorov's team and vision, he said: "I don't know anyone who supports the decision to replace him. Not within the army, not in society."

"I have lots of friends in the military. Lots of them died. I don't want this to go on," Maria Lavrynets, 31, told the BBC at a protest in Ivan Franko square in central Kyiv. "We see [Fedorov's] results. We see the motivation of the soldiers, we should stand for them."

When he was brought in, Fedorov set off to restructure the defence ministry, which many in Ukraine see as too bogged down in bureaucracy and old Soviet-era attitudes.

A former minister of digital transformation, he was active from the early days of Russia's full-scale invasion in 2022 in setting up a volunteer "IT Army of Ukraine" to launch cyber-attacks against Russians.

Later, he led a successful fundraising campaign called the Army of Drones and brought in elements of "gamification" to the war, designing a system that awarded Ukrainian military units with credits for hitting Russian assets.

Fedorov's focus on drones, high-tech warfare and procurement continued after he become defence minister.

In the early days of his tenure he also asked SpaceX founder Elon Musk to stop Russia from using Starlink satellites for drone attacks - a move that caused considerable disruption to Russia's frontline operations and advance.

His ministry also played a significant part in Ukraine's recent attacks on the Moscow-occupied Crimean peninsula, which last month Fedorov vowed to "cut off" from Russia entirely, with the use of mid-range drone strikes.

In a Facebook post shortly after his dismissal, Fedorov listed his achievements and said he would "continue... to defeat the enemy through asymmetry, speed of innovation, and organisational strength".

Prominent blogger Serhii Sternenko, whom Fedorov brought in as an adviser, hailed his former boss as "the best minister of defence in our entire history" and bemoaned the "bureaucratic obstacles and artificial delays" he said had stood in the way of deeper reform.

Pavlo Yelizarov, a renowned drone unit commander, resigned from his position of deputy commander of the Ukrainian Air Force in protest at Fedorov's sacking - a move he called "a great evil for the country's defence capability".