According to the Kremlin, Goar Vartanyan and her late husband, Gevork, were involved in foiling Operation Long Jump -- a Nazi plot to kill the "Big Three" while the Allied leaders were in Tehran for their first meeting during World War II.
Vartanyan died Monday and will be buried in the Troyekurovskoye Cemetery in Moscow, according to Russian state news agency Ria Novosti.
Her husband died in 2012 at the age of 87.
Dmitry Peskov, press secretary to Russian President Vladimir Putin, said in a press conference call Wednesday that the Russian leader offered his condolences.
Peskov said the husband and wife spy duo affected the course of human history.
Vartanyan was born in Gyumri -- in what was then Soviet Armenia -- on January 25, 1926, according to the AFP news agency.
Her family moved to Iran in the early 1930s.
After becoming involved with an anti-fascist group at the age of 16, she worked with Gevork to expose German agents, AFP reports.
In 1951, the Vartanyans moved to the USSR and are believed to have had lengthy careers in the intelligence service.
Gevork Vartanyan received the Hero of the Soviet Union award for his services.
AFP reports that the SVR -- a Russian intelligence agency that succeeded the KGB after the dissolution of the Soviet Union -- said the couple had been involved in "active intelligence work" in "extreme conditions in many countries."