[6] Two of the most infamous operations for which the Irgun were known; the bombing of the British administrative headquarters for Mandatory Palestine in Jerusalem on 22 July 1946 and the Deir Yassin massacre that killed at least 107 Palestinian Arab villagers, including women and children, carried out with Lehi on 9 April 1948.

Among these publications were three books written by David Raziel, who had studied military history, techniques, and strategy:[23] A British analysis noted that the Irgun's discipline was "as strict as any army in the world.

[22] The British authorities believed that some Irgun members enlisted in the Jewish section of the Palestine Police Force for a year as part of their training, during which they also passed intelligence.

In addition to having a daily roll call and the distribution of food and water (usually very little of either), organized talks were held to provide information regarding the actual arrival in Palestine.

In March 1938, David Raziel wrote in the underground newspaper "By the Sword" a constitutive article for the Irgun overall, in which he coined the term "Active Defense": The actions of the Haganah alone will never be a true victory.

Defensiveness by way of offensiveness, in order to deprive the enemy the option of attacking, is called active defense.By the end of World War II, more than 250 Arabs had been killed.

In this manner Yehezkel Altman, a guard in a Betar battalion in the Nahalat Yizchak neighborhood of Tel Aviv, shot at an Arab bus, without his commanders' knowledge.

Demonstrations around the country, as well as pressure from institutions and people such as Dr. Chaim Weizmann and the Chief Rabbi of Mandatory Palestine, Yitzhak HaLevi Herzog did not reduce his sentence.

Furthermore, the opposition within the Yishuv to illegal immigration significantly decreased, and the Haganah began to bring Jews to Palestine using rented ships, as the Irgun had in the past.

This, among other events, encouraged the Irgun to announce a cessation of its activities against the British so as not to hinder Britain's effort to fight "the Hebrew's greatest enemy in the world – German Nazism".

The largest of these revolts was the Warsaw Ghetto Uprising, in which an armed underground organization fought, formed by Betar and Hatzoar and known as the Żydowski Związek Wojskowy (ŻZW) (Jewish Military Union).

The new Irgun leadership, which included Meridor, Yerachmiel Ha'Levi, Rabbi Moshe Zvi Segal and others used the forced hiatus in activity to rebuild the injured organization.

As Eliyahu Lankin tells in his book: Immediately following the failure of Fighting Nation practical discussions began in the Irgun Headquarters regarding a declaration of war.In 1943 the Polish II Corps, commanded by Władysław Anders, arrived in Palestine from Iraq.

However, these hopes were quickly dashed when the government limited Jewish immigration, with the intention that the population of Mandatory Palestine (the land west of the Jordan River) would not be more than one-third of the total.

The King David Hotel bombing and the arrest of Jewish Agency and other Yishuv leaders as part of Operation Agatha caused the Haganah to cease their armed activity against the British.

On February 14, 1947, Ernest Bevin announced that the Jews and Arabs would not be able to agree on any British proposed solution for the land, and therefore the issue must be brought to the United Nations (UN) for a final decision.

According to Bruce Hoffman: "In an era long before the advent of 24/7 global news coverage and instantaneous satellite-transmitted broadcasts, the Irgun deliberately attempted to appeal to a worldwide audience far beyond the immediate confines of its local struggle, and beyond even the ruling regime's own homeland.

"[22][24] On April 16, 1947, Irgun members Dov Gruner, Yehiel Dresner, Eliezer Kashani, and Mordechai Alkahi were hanged in Acre Prison, while singing Hatikvah.

Approximately thirteen hours later the hostages were hanged in retaliation by the Irgun and their bodies, booby-trapped with an explosive, afterwards strung up from trees in woodlands south of Netanya.

At the same time though, it published announcements calling on the Arabs to lay down their weapons and maintain a ceasefire: The National Military Organization has warned you, if the murderous attacks on Jewish civilians shall continue, its soldiers will penetrate your centers of activity and plague you.

[59] In Jerusalem, two days later, Irgun members in a stolen police van rolled a barrel bomb into a large group of civilians who were waiting for a bus by the Jaffa Gate, killing around sixteen.

[64] The Deir Yassin massacre was carried out in a village west of Jerusalem that had signed a non-belligerency pact with its Jewish neighbors and the Haganah, and repeatedly had barred entry to foreign irregulars.

Their objective was "to prevent constant military traffic in the city, to break the spirit of the enemy troops [and] to cause chaos among the civilian population in order to create a mass flight.

"[73] High Commissioner Cunningham wrote a few days later "It should be made clear that IZL attack with mortars was indiscriminate and designed to create panic among the civilian inhabitants.

[77] References to the Irgun as a terrorist organization came from sources including the Anglo-American Committee of Inquiry,[78] newspapers[79][80][81][82][83] and a number of prominent world and Jewish figures.

"[88] Irgun attacks prompted a formal declaration from the World Zionist Congress in 1946, which strongly condemned "the shedding of innocent blood as a means of political warfare.

"[89] The Israeli government, in September 1948, acting in response to the assassination of Count Folke Bernadotte, outlawed the Irgun and Lehi groups, declaring them terrorist organizations under the Prevention of Terrorism Ordinance.

[2] In 1948, The New York Times published a letter signed by a number of prominent Jewish figures including Hannah Arendt, Albert Einstein, Sidney Hook, and Rabbi Jessurun Cardozo, which described Irgun as "a terrorist, right-wing, chauvinist organization in Palestine".

Max Abrahms writes that the Irgun "pioneered the practice of issuing pre-attack warnings to spare civilians", which was later emulated by the African National Congress (ANC) and other groups and proved "effective but not foolproof".

U.S. military intelligence found that "the Irgun Zvai Leumi is waging a general war against the government and at all times took special care not to cause damage or injury to persons".