What can you infer about what might have been western european concerns at the outset of the invasion of south korea?

During the offset of the invasion of North Koreans to the South during the Korean war there are a lot of concerns whether to aid the South or avoid the conflict. One of this is whether the USSR would join the war if the United Nations Allied Forces would aid South Korea and whether the war would escalate from a small region conflict into another world war that would lead to a nuclear war between two superpowers - the US and the USSR.