Both Vice President Kamala Harris and former President Donald Trump took a break from the campaign trail Thursday, but both took shots at each other during public appearances.Harris met with Ukraine's President Volodymyr Zelenskyy at the White House. She previewed her vision for peace in Ukraine and blasted suggestions that Ukraine should surrender any of its territory."These proposals are the same as those of Putin. And let us be clear: They are not proposals for peace. Instead, they are proposals for surrender," Harris said.Trump on Wednesday criticized Zelenskyy, saying he refused to make a deal with Putin.Also on Thursday, Harris joined President Biden to mark the first anniversary of the establishment of the White House Office of Gun Violence Prevention, with Harris at the helm.Harris called for common-sense gun control measures."It is a false choice to suggest either you are in favor of the Second Amendment or you want to take everyone's guns away," Harris said.RELATED STORY | Zelenskyy continues push for Ukraine support in Washington meetingsIn New York Thursday, Trump held a press conference where he lashed out at Harris on the issue of migration at the southern border."She keeps talking about how she supposedly wants to fix the border," Trump said. "We would merely ask why didn't she do it four years ago?"Harris is expected to visit the border during a campaign stop in Arizona.