STOCKHOLM, Nov 11 (Reuters) - Swedish prosecutors on Friday indicted two brothers for gross espionage on behalf of Russia, saying the alleged crime could be detrimental to the Nordic country's security."The suspicion concerns very serious criminality directed against Sweden's intelligence and security system.The two men are suspected of having provided Russian intelligence agency GRU with classified information for a decade, starting in 2011.One of the brothers have worked for the Swedish Security Police and the Armed Forces during the period, according to court documents."The information that has been obtained, transmitted and divulged could, by the fact that if it comes into the hands of a foreign power, result in detriment to Sweden's security," the Prosecutor's Office said."