Three years into the war with Russia, President Zelensky appears to have become embroiled in a personal feud with the leader of Ukraine’s most powerful ally.

President Donald Trump said Friday it was unimportant for Ukrainian President Volodymyr Zelensky to be in meetings to negotiate an end to the Russia-Ukraine war—escalating a feud that began earlier this week after Zelensky rejected a deal to give the U.S. rights to some of Ukraine’s mineral resources.