See subject. From Wiki cite (surely not original text of memo):
US,UK,Russia to Ukraine: Give up your nukes.
US,UK,Russia to Ukraine:
[li]to respect Ukrainian independence and sovereignty within its existing borders;[/li][li]to protect Ukraine from outer aggression and not to conduct aggression toward Ukraine;[/li][li]not to put economic pressure on Ukraine in order to influence her politics;[/li][li]not to use nuclear arms against Ukraine. [/li][/ol]