They were arrested on Saturday evening after one of them tried to force his way into a former arms factory in central town of Gramsh that is now used for destroying derelict weapons.

According to police, one Russian national jumped the fence, took photographs of the factory and attacked the soldiers who confronted him, injuring two of them with pepper spray.

The two other suspects -- a Russian and a Ukrainian -- were arrested in a car parked near the factory, where the police also discovered laptops, drones and other cameras.

They are being investigated for "gathering secret information of military or any other character in order to be supplied to a foreign power, which violates the country's independence", said the presiding judge in Elbasan court, Pajtime Fetahu.

However, the court dropped another, more serious charge that was requested by the prosecutor's office that would directly accuse them of providing information to another country.

If convicted, the foreign nationals could face up to ten years behind bars.

Their appointed lawyers told media that their clients reject all accusations, and demanded their release.

The hearing was held behind closed doors, and no details were provided as to why the suspects might have been interested in the site.