them. Both the Israelis and the Arabs used this time to improve their positions, a direct violation of the terms of the ceasefire. Reinforcements At the time of the truce, the British view was that "the Jews are too weak in armament to achieve spectacular success". As the truce commenced, a British officer stationed in Haifa stated that the four-week-long truce "would certainly be exploited by the Jews to continue military training and reorganization while the Arabs would waste [them] feuding over the future divisions of the spoils". During the truce, the Israelis sought to bolster their forces by massive import of arms. The IDF was able to acquire weapons from Czechoslovakia as well as improve training of forces and reorganisation of the army during this time. Yitzhak Rabin, an IDF commander at the time of the war and later Israel's fifth Prime Minister, stated "[w]ithout the arms from Czechoslovakia... it is very doubtful whether we would have been able to conduct the war". The Israeli army increased its manpower from approximately 30,000–35,000 men to almost 65,000 during the truce due to mobilisation and the constant immigration into Israel. It was also able to increase its arms supply to more than 25,000 rifles, 5,000 machine guns, and fifty million bullets. As well as violating the arms and personnel embargo, they also sent fresh units to the front lines, much as their Arab enemies did. During the truce, Irgun attempted to bring in a private arms shipment aboard a ship called Altalena. Fearing a coup by the Irgun (at the time the IDF was in the process of integrating various pre-independence political factions), Ben-Gurion ordered that the arms be confiscated by force. After some miscommunication, the army was ordered by Ben-Gurion to sink the ship. Several Irgun members and IDF soldiers were killed in the fighting. UN mediator Bernadotte The ceasefire was overseen by UN mediator Folke Bernadotte and a team of UN Observers made up of army officers from Belgium, United States, Sweden and France. Bernadotte was voted in by the General Assembly to "assure the safety of the holy places, to safeguard the well being of the population, and to promote 'a peaceful adjustment of the future situation of Palestine'". Folke Bernadotte reported: During the period of the truce, three violations occurred ... of such a serious nature: the attempt by ...the Irgun Zvai Leumi to bring war materials