On 14 July Lumumba and Kasa-Vubu sent a telegram to the United Nations (UN), stating that peacekeepers were requested to guard the Congo's sovereignty against Belgian aggression and warning that if the request was not speedily fulfilled they would turn to the Bandung Powers for assistance. The following day they sent a message to Soviet Premier Nikita Khrushchev from Kindu, asking that he monitor the situation in the Congo closely. In New York City the UN Security Council adopted UNSC Resolution 143, calling upon Belgium to withdraw its troops and authorising the Secretary-General to send military and technical assistance to the Congo in consultation with the government to restore law and order. This resulted in the establishment of a large UN multinational peacekeeping force (generally known by its French acronym of ONUC). Foreign contingents arrived in the capital shortly thereafter. UN Secretary General Dag Hammarskjöld later stated that these were to form a "temporary security force" that, although acting with the consent of and performing some of the tasks of the government, was completely under UN command. Meanwhile in the same period of time, Baluba throughout Katanga and Kasai became the subject of violent attacks. Kalonji and his allies made an official call to the Baluba across the Congo to return to their "homeland" in the southern portion of the province on 14 July. Initially, they envisaged the division of Kasai in two in order to allow for the creation of a quasi-autonomous MNC-K and Luba-dominated provincial government. Rapidly, however, Kalonji realised that the chaos in the rest of the Congo could be used to secede unilaterally and declare full local independence. On 9 August 1960, Kalonji declared the region of south-eastern Kasai to be the new Autonomous State of South Kasai ("État autonome du Sud-Kasaï"). South Kasai's secession was supported by Belgian corporate interests, chiefly the Forminière mining company. When South Kasai seceded, ANC troops were already fighting Katangese troops in the Kasai region. The arrival of the ONUC was initially welcomed by Lumumba and the central government who believed the UN would help suppress the secessionist states. ONUC's initial mandate, however, only covered the maintenance of law and order. Viewing the secessions as an internal political matter, Hammarskjöld refused to use UN troops to assist the central Congolese government against them; he argued that doing so would represent a loss of impartiality and breach Congolese sovereignty.