Lars Findsen, the head of Denmark's foreign intelligence unit, has been remanded in custody over his involvement in a case of "highly classified" information leaks, according to public broadcaster DR.

Denmark's two intelligence services have been in disarray since four current and former employees were arrested in December on suspicion of leaking highly classified information, a case that could harm the agencies' reputation abroad.

While the investigation is ongoing, Findsen is the only person who remains in custody. The news was revealed at a court hearing on Monday when a publication ban was lifted, as reported by DR and other local media.

"I want the charges brought forward and I plead not guilty. This is completely insane," Findsen told reporters at the hearing, where a judge decided to extend Findsen's custody until Feb. 4, according to newswire Ritzau.

The public prosecutor's office declined to comment on the case, and Reuters was unable to reach Findsen or his lawyer right away.

The case, about which authorities have released very little information, is being prosecuted behind closed doors, which means that the specific charges and nature of the leaked information have not yet been made public.

Four intelligence officials are charged

The four intelligence officials were charged on Monday with violating a section of the penal code, which includes treason, by "having imparted highly classified information," according to the Danish Security and Intelligence Service (PET).

If highly classified information is passed on, it can cause "serious or extremely serious damage" to Denmark or other European Union or NATO countries, according to the report. The maximum prison sentence for such an offense is 12 years.

The case revolves around classified information leaks to Danish media outlets, according to DR, which cited unnamed sources.

The Danish Defence Intelligence Service shared raw data from information cables with the US National Security Agency in 2020, implying that the NSA had access to Danish citizens' personal data and private communications.

Last year, several other domestic news outlets published reports based on confidential information about Danish intelligence activities.

In a separate case, Findsen and four other intelligence officials were suspended in August 2020 after allegations of serious wrongdoing were made by an independent board overseeing the intelligence unit. An investigating commission rejected those allegations last month, and the suspensions were lifted.