Finland's customs authority announced it was investigating an attempt by Russia to breach EU sanctions after intercepting sensitive documents. Nearly 30 boxes of sensitive documents related to nuclear power plant construction were allegedly found on their way to Russia earlier this week.

The Economic Crime Investigation Unit of Finnish Customs said: "The preliminary investigation has focused on a significant number of archive documents that were attempted to be taken to Russia from a warehouse located in Kymenlaakso. Based on the preliminary investigation, some of the data is classified as material subject to sanctions against Russia." Finnish Customs accused the managing director of a construction company involved in the project of being a suspect, but did not release any more information.

It added that any potential charges will only be brought against those involved once the investigation is complete.

The Nordic country has two power plants - Loviisa and Olkiluoto - that house five nuclear reactors. The plants' owners confirmed that they were not part of the investigation.

There were also plans for another plant at Hanhikivi that would have used a reactor from the Russian energy corporation Rosatom, but these were dropped after the onset of the war in Ukraine in 2022.

Finland shares a 833-mile border with Russia, which it closed in December 2023 after joining NATO and accusing Moscow of deliberately sending over migrants in a hybrid operation.

Just days ago, the Finnish government announced it would keep the border closed "until further notice", but asylum applications will still be accepted at the country's air and maritime border crossings.

It said: "Instrumentalised migration is one way that Russia can put pressure on and affect the security and social stability of Finland and the EU.

"Based on information available to the Finnish authorities, the risk that instrumentalised migration will resume and expand as seen previously remains likely."