VILNIUS, Lithuania — A gathering between President Biden and Ukrainian President Volodymyr Zelensky is underway on day two of the annual summit for NATO leaders. “The main target is on safety and the whole lot that enhances it,” Zelesnky wrote on Twitter forward of the dialogue. “Will probably be significant.” Earlier Wednesday, the Group of Seven nations — Canada, France, Germany, Italy, Japan, the UK and america — issued a joint declaration of “unwavering” assist for Ukraine.