A South Korean marine who had attempted to enter Ukraine to fight for the country against Russia while on leave was denied entry and is now at a Polish border checkpoint post.

According to a South Korean Foreign Ministry official on Wednesday, the marine had tried to enter Ukraine from Poland but was denied access at a Ukrainian border checkpoint.

Ukrainian authorities then took him to a border checkpoint in Poland. South Korean embassy officials are on standby outside the checkpoint post attempting to persuade him to leave, but the marine is refusing to step out.

He may face punishment once back in South Korea. An active duty soldier leaving the nation without approval while on leave is considered to be deserting their military service.