BELGRADE, Serbia — Serbian police brought in a well-known Serbian doctor and other vocal anti-vaccination activists for questioning Thursday, saying they are jeopardizing the Balkan country’s successful coronavirus inoculation drive.

Serbian state TV said psychiatrist Jovana Stojkovic, a leading figure in the country’s anti-vaccination movement, was taken to a police station in Belgrade on accusations that she has been spreading “fear and panic” with her social media posts and public appearances.

Stojkovic, who leads a small far-right party, has frequently voiced anti-vaccination conspiracies.

At least five other people, including a former Serbian women’s national basketball team player, were reportedly questioned by police on Thursday in an apparent crackdown against Serbia’s growing anti-vaccination movement.

Serbian Justice Minister Maja Popovic said the Interior Ministry and state prosecutors were acting according to the law.

“All the perpetrators of criminal acts must be processed, especially when they threaten public health,” the statement said.

Dozens of supporters greeted Stojkovic as she was released by police in the late afternoon, carrying a banner reading “Stop the COVID fascism.”

Serbia has one of the highest inoculation rates in Europe, mainly thanks to the government’s large purchases of China’s Sinopharm and Russia’s Sputnik V vaccines. The Balkan nation is also using the vaccines developed by Pfizer-BioNTech and Oxford-AstraZeneca.

Although over 2 million of Serbia’s 7 million people have so far received at least one vaccine shot, Serbia has seen a notable decline in the number of residents signing up for jabs. Officials and doctors link the drop-off to an increasingly vocal anti-vaccine movement.

Thousands of vaccine-seekers from countries neighboring Serbia last month flocked to Belgrade after authorities offered foreigners free jabs for all those who showed up. They all received AstraZeneca jabs that faced expiration dates because of the lack of interest for that vaccine among Serbs.

Serbia has seen over 5,300 deaths in the pandemic.