“The information that has been obtained, transmitted and divulged could… if it comes into the hands of a foreign power, result in detriment to Sweden’s security”, chief public prosecutor Per Lindqvist said in a statement.

The two brothers were identified in the charge sheet as Payam Kia, 35, and Peyman Kia, 42. According to Swedish media reports, they are of Iranian origin. Peyman Kia has served in Sweden’s intelligence service Säpo and intelligence units in the Swedish army. 

According to Sweden’s paper of reference, Dagens Nyheter, he at one point worked for the Office for Special Information Gathering (KSI), the most secret section of the military secret service.

He is accused of illegally acquiring information during his employment with Säpo and the armed forces.

Payam Kia is meanwhile accused of “participating in the planning of the deed and handling contacts with Russia and the GRU, including the handover of information and receiving compensation”.

The pair, who risk life sentences if found guilty, have denied the allegations, according to Swedish media.

Defence Minister Pal Jonsson told parliament on Friday the case was “very sensitive” and the country had strengthened its security since the pair’s arrest a year ago.