At dawn on Saturday, June 29, 1946, a curfew was imposed throughout the country and seventeen thousand troops were dispatched to institutions and settlements to seize arms and documents and to arrest the leaders of the Yishuv and of the Haganah. The Mandate government announced that it was resolved to eradicate terror and violence, and that the army operations had been sanctioned by the Cabinet in London. Operation Agatha, as it was termed by the British, came as a surprise and achieved most of its aims. A great deal of intelligence groundwork was done and special detention camps were prepared at Rafiah, without the Haganah Intelligence Service suspecting anything. In Jerusalem, the British entered the Jewish Agency offices and, after conducting a thorough search of rooms and archives, confiscated documents, which they loaded onto three large trucks. Among them were telegrams, which provided clear evidence of the role of the Jewish Agency in leading the United Resistance. They included the cable sent by the Chairman of the Jewish Agency Executive (David Ben-Gurion) to the Head of the Haganah Command (Moshe Sneh) telling him to launch an offensive against the Mandate Government immediately; the agreement between the Haganah, Irgun and Lehi, and cables giving the go-ahead for Irgun and Lehi actions against the British within the framework of the United Resistance. Also found were the texts of broadcasts by Kol Israel (the Resistance's secret broadcasting station) stating, among other things, that everything possible would be done 'to impede the transfer of British bases to Palestine'.

Searches were conducted and arrests made in many kibbutzim, but the British scored their greatest success at Kibbutz Yagur in the Zevulun Valley. They searched for a week, apparently on the basis of a reliable tip-off. The kibbutz members offered passive resistance, but were dispersed with tear gas and incarcerated in detention areas set up by the soldiers. At first the search proceeded in routine fashion, but after the first arms' cache was found, the attitude changed and the British started digging under the floors, literally leaving no stone unturned in their search for arms. After a week, they had uncovered a great deal of booty, including more than 300 rifles, some 100 mortars (2"), more than 400,000 bullets, about 5,000 grenades and 78 revolvers. The spoils were displayed at a press conference at the kibbutz, and the British left only after arresting all the men on the Yagur.

During Black Sabbath, more than 2,700 people were arrested throughout the country and taken to the Rafiah detention camp. The last of them were released only two months later.

The Haganah at first reacted with outrage. The Kol Yisrael announcer declared dramatically:
Our backs are to the wall! We will fight back.
The Haganah command decided to carry out three operations against the British authorities. The first was a Palmach raid on the Bat Galim army camp, in order to requisition weapons (according to Haganah Intelligence Service information, the weapons confiscated at Yagur were being stored there). The second mission, entrusted to the Irgun, was the blowing up of the King David Hotel, where the offices of the Mandatory government and the British military command were located. The Lehi was allotted the task of blowing up the adjacent David Brothers building, which housed government offices. In a letter to Begin, Sneh wrote:1

a) At the earliest possible opportunity, you are to carry out the operation at the 'chick' (code name for King David Hotel) and at the house of "your servant and messiah" (code name for David Brothers building). Inform me of the date. Preferably at the same time. Do not reveal the identity of the implementing body - either by announcing it explicitly or by hinting.

b) We too are preparing something - will inform you of details in good time.

c) Exclude TA (Tel Aviv) from any plan of action. We are all interested in preserving TA - as the center of Yishuv life and the center of our own activities. If, as the result of any action, TA is immobilized (curfew, arrests), this will paralyse us and our plans as well. And the important objects of the other side are not focused here. Hence, TA is 'out of bounds' for the forces of Israel.

1.7.46. M. [Moshe Sneh]."

While preparations for the operations were at their height, Meir Weisgal arrived at Sneh's hideout. Weisgal was on a personal mission from Chaim Weizmann, President of the Zionist Organization (Weizmann himself was then ailing at his home in Rehovot). Weisgal told Sneh that Weizmann urged that the armed struggle against the British be halted. Among other things, Weisgal quoted Weizmann as saying:
"In other countries it is accepted that the president is the commander in chief of the armed forces. I have never sought this authority nor has it ever occurred to me to interfere in your affairs. For the first and only time, I am exercising this right and demanding of you that you cease all this activity."
Weizmann demanded an immediate answer, and announced that if his request was rejected, he would resign and publicly announce the reasons for his resignation. Sneh, who was opposed to the armed struggle against the British, informed Weisgal that he could not decide this matter alone, and would submit Weizmann's request to the X Committee.2 The committee debated the question of the powers of the president of the Zionist Organization, but eventually decided, by majority vote, to accede to Weizmann's request. Sneh, who opposed the resolution, resigned from his post as head of the Haganah's national command, but remained liaison officer with the Irgun and Lehi. Sneh met with Begin, did not inform him of the X Committee's resolution, and merely requested that the assault on the King David Hotel be postponed. Sneh then decided to leave for Paris to attend a meeting of the Jewish Agency Executive, which was to discuss the continued struggle against the Mandatory government. Before leaving the country, on July 19, he sent Begin another note:

I have heard from my comrades about the recent conversation. If my personal appeal still holds weight with you, I beg you to delay the scheduled actions for another few days".

As a result of Sneh's appeal, the attack on the King David Hotel was scheduled for July 22, 1946. Because of coordination problems, the Lehi decided to cancel its plan to blow up the David Brothers building.

1. Jabotinsky Institute,k-4 1/11/5
2. The x committee was the supreme political committee to which were submitted the operational plans of the United Resistant (without specification of the target and exact date). The plans were implemented only after approval by the committee.