Belgian police have swooped on the European Parliament today as part of an ongoing probe into an parliamentary employee who prosecutors say may have played a role in spreading Russian propaganda ahead of an EU assembly election.

Investigators searched the unnamed assistant's home and office at the European Parliament - both in Brussels - according to federal prosecutors, while French authorities searched his office at the EU's assembly building in Strasbourg.

Prosecutors said the searches were part of an investigation into possible Russian interference whereby members of the European Parliament were approached and paid to promote Russian propaganda via the "Voice of Europe" news website.

They added in a statement: "There are indications that the European Parliament employee concerned played a significant role in this."

Prosecutors said the searches were part of an investigation into possible Russian interference in the European Parliament

The European Parliament has said it will not comment on the investigation, which remains ongoing.

But a parliamentary spokesperson said: "When and if requested to, the European Parliament fully cooperates with law enforcement and judicial authorities to assist the course of justice and will continue to do so. It is this context that access to an office was provided."

Voice of Europe has said in an unsigned article on its website that it "categorically rejected" the EU action.