By Pavel Polityuk KYIV (Reuters) -Russian-installed leaders in occupied areas of four Ukrainian regions on Tuesday set out plans for referendums on joining Russia, a challenge to the West that could sharply escalate the war and sparked condemnation from Ukraine and its allies. “The Russians can do whatever they want. It will not change anything,” Ukraine’s Foreign Minister Dmytro Kuleba said in response to reporters’ questions at the United Nations. In a tweet, he added: “Ukraine has every right to liberate its territories and will keep liberating them whatever Russia has to say.” U.S. Nationa…