Ștefan Plavăț (April 24, 1913 – June 18, 1944) was a Romanian communist activist, leader of a resistance group active in South-Western Romania during World War II.
The Pomeranian Griffin secret military organization (Polish: "Tajna Organizacja Wojskowa Gryf Pomorski" ) was a Polish anti-Nazi resistance group active in Pomerania and East Prussia during World War II.
 A major Polish resistance organization in the Pomerania region, at its height in 1943 it might have had as many as 20,000 members, although only about 500 were active partisans in the forests (leśni).
Jacoba van Tongeren (Tjimahi near Bandung, Dutch East Indies) 14 October 1903 – Bergen (The Netherlands), 15 September 1967) was a resistance fighter, the founder and leader of Groep 2000, a resistance group during the Second World War.
 Jacoba van Tongeren is the only woman to have created and led a resistance group during the war.
 In 1990, Yad Vashem honoured Jacoba van Tongeren as Righteous Among the Nations.
Yitzhak Wittenberg (1907—July 16, 1943) (Hebrew: יצחק ויטנברג‎ ) was a Jewish resistance fighter in Vilnius during World War II.
 He became famous as the leader of the Fareynikte Partizaner Organizatsye, a resistance group in the Vilna Ghetto.
 When the Germans learned about the existence of the group, they made a request to the head of the Jewish council, Jacob Gens, that Wittenberg should be surrendered to them.
 Gens invited Wittenberg among others to his office where he had him arrested and later handed him over to the Gestapo.
This list contains the names of individuals involved in the German Resistance against Nazism, but is not a complete list.
 Names are periodically added, but not all names are known.
 There are both men and women on this list of "Widerstandskämpfer" ("Resistance fighters") primarily German, some Austrian or from elsewhere, who risked or lost their lives in a number of ways.
 They tried to overthrow the National Socialist regime, they denounced its war criminals, tried to prevent World War II and sabotaged German attacks on other countries.
 Some tried to protect those who were being harmed and persecuted by the Nazis, others merely refused to contribute to the Nazi war effort.
 Most of those on the list worked with others; their affiliated resistance group or groups are listed.
 Where no group is mentioned, the individual acted alone.
Petre Ion Gheorghe (also known as Petre Ivan Gheorghieff or Gheorghiev; March 19, 1907 – February 8, 1943) was a Bulgarian-born Romanian communist and anti-fascist resistance member, executed by Romania for espionage and treason.
 Having risen through the ranks of the Union of Communist Youth, he was the leader of the strongest communist resistance group during the first part of World War II in Romania.
Holger Danske (] ) was a Danish resistance group during World War II.
 It was created by veteran volunteers from the Winter War who had fought on the Finnish side against the Soviet Union.
 It was among the largest Danish resistance groups and consisted of around 350 volunteers towards the end of the war.
 The group carried out about 100 sabotage operations and was responsible for around 200 executions of informers who had revealed the identity and/or the whereabouts of members of the resistance.
 The group was named after the legendary Danish hero Holger Danske.
Missak Manouchian (Western Armenian: Միսաք Մանուշեան ; ] , 1 September 1906 – 21 February 1944) was a French-Armenian poet and communist activist.
 An Armenian Genocide survivor, he moved to France from an orphanage in Lebanon in 1925.
 He was active in communist Armenian literary circles.
 During World War II, he became the military commissioner of FTP-MOI, a group consisting of European immigrants, including many Jews, in the Paris region which carried out assassinations and bombings of Nazi targets.
 According to one author, the Manouchian group was the most active French Resistance group.
 Manouchian and many of his comrades were arrested in November 1943 and executed by the Nazis in Fort Mont-Valérien on 21 February 1944.
 He is considered a hero of the French Resistance.
The Fareynikte Partizaner Organizatsye (Yiddish: פֿאַראײניקטע פּאַרטיזאַנער אָרגאַניזאַציע; "United Partisan Organization"; referred to as FPO by its Yiddish initials) was a Jewish resistance organization based in the Vilna Ghetto that organized armed resistance against the Nazis during World War II.
 The clandestine organisation was established by Zionist as well as Communist partisans.
 Their leaders were writer Abba Kovner and Yitzhak Wittenberg.
The General Sabotage Group of Belgium (French: "Groupe Général de Sabotage de Belgique" ), more commonly known as Groupe G, was a Belgian resistance group during the Second World War, founded in 1942.
 Groupe G's activities concentrated particularly on sabotage of German rail lines and it is widely considered to have been the most effective resistance group in Belgium during the period.

Question: Where was the leader of the resistance group referred to as FPO active during World War II?
Answer: Vilnius