During the next fortnight fighting by organised units became more frequent. Regular forces from Syria and Lebanon entered Palestine to assist the local Arabs. And on 15-16 May, as the mandate came to an end, the governments of Egypt and Transjordan informed the UN that their forces were entering Palestine to 'maintain security and order' and to 'protect the unarmed Arab population': in effect to make war on the newly declared state. Until the very day before the mandate came to an end, the Special Assembly had still been devoting itself to securing a long-term settlement of the Palestine problem. With a questionable sense of priorities it had devoted itself above all else to the question of internationalising Jerusalem. Only just before the deadline, as large-scale fighting increased, did it turn its attention to the more immediate, but far more urgent, object of securing a truce (a question on which the Security Council had appeared equally indifferent).
It entrusted this task primarily to the Truce Commission, which had been first set upon 23 April. The job of securing a political settlement, under the terms of its resolution of 14 May, it placed in the hands of the mediator it had then appointed. In the original resolution, no individual was named for this task. But within a few days, a committee of permanent members, to whom the task of choosing the mediator had been delegated, announced the appointment of Count Bernadotte, president of the Swedish Red Cross.
With that the Assembly dispersed. For three days the Security Council remained totally inactive, while the fighting intensified. Various attempts by the Secretary-General to stimulate it to action had no effect. Lie (who was a strong supporter of the new state) regarded the attack by the Arab armies on Israel as the most serious act of aggression the organisation had yet had to confront. He strongly urged on the US and British governments the need for a prompt and firm UN response. And he addressed a personal letter to all the permanent members, demanding that the UN should act quickly.
Despite this it was only on 18-19 May that the Security Council finally met to consider the fighting. The United States then proposed a resolution, under Chapter VII of the Charter, ordering a ceasefire within thirty-six hours - a demand which would have been mandatory. This was not accepted. The Council agreed only to her proposal that it should send a questionnaire to the Arab governments, the Arab Higher Committee and the 'Jewish authorities in Palestine' asking how far their forces were involved in the fighting, the areas they controlled, and so on. Nothing else was to be done till the answers to this were received.
This was an extraordinarily long-winded procedure, and the replies inevitably took several days to come in. When they did arrive, they contained more propaganda than fact. Each party tried to show that it controlled large areas of Palestine, and was attempting to hold them against violent incursions by the enemy. The information made no significant difference to the action the Council took. But at least intense discussion now began about the terms of a ceasefire. The Council eventually adopted a British amendment to the resolution first proposed by the United States. This avoided invoking Chapter VII, but 'called on' the authorities concerned to implement a ceasefire within thirty-six hours.