It is noted that investigators searched the aide's home, office in the European Parliament, as well as his office in Strasbourg.

According to prosecutors, such actions were part of an investigation into possible Russian interference, in which MEPs were approached with a proposal to spread Russian propaganda through the Voice of Europe news site and paid for it.

"There are indications that the relevant MEP played a significant role in this", the prosecutor's office said in a statement.

At the same time, the European Parliament said it could not comment on the incident, but it "fully cooperates with law enforcement and judicial authorities to facilitate the administration of justice and will continue to do so".

The prosecutor's office has not yet named the MEP or the MP whose assistant he was.

Reuters adds that voters in 27 EU countries will go to the polls on June 6-9 to elect 720 MEPs. According to observers, voters are likely to be shrouded in lies and disinformation.

• On March 17, the European Union imposed sanctions on four Russian propaganda outlets: Voice of Europe, RIA Novosti, Izvestia, and Rossiyskaya Gazeta, banning them from broadcasting and publishing in the EU.