Football club Port Vale has said it would fully back any police action against any of its fans involved after trouble broke out between fans of Wolverhampton Wanderers and the team.
Port Vale club secretary Bill Lodey said: "The club are bitterly disappointed regarding the violence that has been reported in Burslem town centre.
"We will fully support any actions taken by the police in apprehending those responsible and they can expect severe penalties."
More top news
Mr Kim has made two recent visits to China.
The study looked at the development of 422 children over the course of eight years.
The president said they will come into force if China refuses to change its practices.