US Secretary of State Marco Rubio has described Russia 's ongoing invasion of Ukraine as a " proxy war " between the United States and Russia , calling for an end to the conflict. Rubio stated in an interview with Fox News that the war is a prolonged struggle between the two nuclear powers, with the US aiding Ukraine. However, he acknowledged that no concrete plan exists to resolve the war. Rubio criticized the strategy of continuing to provide Ukraine with support indefinitely, calling it