Former Swedish national security advisor Henrik Landerholm has been charged with negligence involving classified information.

The charges stem from an incident where Landerholm left secret documents in an unlocked cabinet at a conference center.

The documents, deemed sensitive to national security, were found by a cleaner with alleged ties to violent extremism.

Landerholm denies wrongdoing, claiming he was unaware of the documents' classified nature.

The case has raised concerns about Sweden's security protocols, with the documents reportedly left unattended for two nights.

The trial will include testimony from six witnesses, including government officials.

Justice Minister Gunnar Strömmer has refrained from commenting further, citing the ongoing legal process.