With just under 50 percent of the vote in the first election round last month, Milanović failed to secure an outright victory. The runoff will take place Jan. 12, pitting him against Dragan Primorac from the ruling Croatian Democratic Union.

According to CIR, accounts “featuring pro-Russian government imagery and hashtags” regularly posted content praising Milanović on social media, including X and Facebook, in “two waves”: After he voiced his opposition to sending Croatian troops to Ukraine, and after the first round of the election.

“One seemingly inauthentic Facebook account identified by researchers was found to post over 100 times a day and mainly shared images attacking Primorac or supporting Milanovic,” the report claims.

The report comes hot on the heels of the shock victory of virtually unknown ultranationalist, pro-Russia candidate Călin Georgescu in the first round of Romania’s presidential election in late November. Romania’s top court later annulled the election after it was revealed in declassified Romanian intelligence documents that Georgescu had benefited from a Russia-style booster campaign on TikTok.

“Pro-Russian, anti-EU, and anti-NATO bot networks” worked to boost incumbent Croatian President Zoran Milanović ahead of the Dec. 29 first round of the country’s presidential election. | Damir Sencar/Getty Images

Milanović’s spokesperson did not immediately respond to POLITICO’s request for comment.