Mussolini made it clear that he could not invade Abyssinia without first conquering Egypt and Sudan; they intended unification of Libya with Italian East Africa. The British Imperial General Staff prepared for military defence of the region, which was thin on the ground. The British ambassador blocked Italian attempts to secure a Non-Aggression Treaty with Egypt-Sudan. But Mahmoud was a supporter of the Grand Mufti of Jerusalem; the region was caught between the Empire's efforts to save the Jews, and moderate Arab calls to halt migration.