While the FAN was supplied economically and militarily by Sudan and Egypt, Goukouni received the armed support of Kamougué's FAT and Acyl's CDR shortly after the beginning of the battle, and was provided with Libyan artillery. On 6 June, the FAN assumed control of the city of Faya. This alarmed Goukouni, and he signed, on 15 June, a Treaty of Friendship with Libya. The treaty gave Libya a free hand in Chad, legitimising its presence in that country; the treaty's first article committed the two countries to mutual defence, and a threat against one constituted a threat against the other.