Ukraine's President Volodymyr Zelenskyy will on Saturday make his first visit to Serbia since Russia's invasion, a report said Thursday, highlighting the symbolic importance of the trip to Moscow's traditional ally.

"We need to pull the Serbs away from Russia's side," a senior Ukrainian official told the Agence France-Presse (AFP), calling Zelenskyy's visit to Belgrade a "slap in the face for the Russians."

Zelenskyy – who has toured much of the world to whip up support for Ukraine's defense against the Russian invasion – has not visited the country since he became president in 2019.

Serbia is seen as one of the most Moscow-friendly countries in Europe.

It has not sanctioned Russia over its 2022 invasion and has maintained close energy ties.

President Aleksandar Vucic has held talks with President Vladimir Putin in Moscow – a rare visit by a European leader amid the invasion – where he called for strengthened cooperation and trade.

Serbia is formally vying to join the European Union, though Brussels has bristled at its maintenance of warm ties with Moscow.