The Czech intelligence agency said Belarus managed to create the network because its diplomats are able to freely travel across European countries.
The Czech Republic's counter-intelligence agency said on Monday that it has broken up a spy network being built in Europe by Belarus in a joint operation with the intelligence services of Hungary and Romania.
The Czech agency, also known as BIS, said in a statement that a team of European agents discovered spies in several European countries from Belarus' main security agency, KGB.
It said a former deputy head of Moldovan intelligence service SIS who handed over classified information to KGB was among them.
The Czechs also expelled a Belarusian agent who was operating under the cover of a diplomat. That person was given 72 hours to leave the country, the Czech Foreign Ministry said on Monday.
The Czech agency said Belarus managed to create the network because its diplomats are able to freely travel across European countries.
"To successfully counter these hostile activities in Europe, we need to restrict the movement of accredited diplomats from Russia and Belarus within the Schengen (borderless) area," BIS head Michal Koudelka said in a statement.
The agency didn't immediately offer any further details.
The ongoing international investigation has been supervised by the European Union's judicial cooperation agency, Eurojust.
Belarus is led by President Aliaksandr Lukashenka who is a close ally of Russian President Vladimir Putin.
His country allowed Russia to use Belarusian territory as a staging ground for Moscow's full-scale invasion of Ukraine in 2022 and later allowed the deployment of Russian tactical nuclear missiles.