After delivering a virtual address to Congress, Ukrainian President Volodymyr Zelenskyy spoke exclusively with NBC News’ Lester Holt about the “fairly difficult” negotiations with Russia, whether he believes the U.S. will reverse its decision not to supply fighter planes, and President Biden’s concern about World War III. “Nobody knows whether it may have already started,” Zelenskyy said.  » Subscribe to NBC News: http://nbcnews.to/SubscribeToNBC » Watch more NBC video: http://bit.ly/MoreNBCNews NBC News Digital is a collection of innovative and powerful news brands that deliver compelling, diverse and engaging news stories. NBC News Digital features NBCNews.com, MSNBC.com, TODAY.com, Nightly News, Meet the Press, Dateline, and the existing apps and digital extensions of these respective properties. We deliver the best in breaking news, live video coverage, original journalism and segments from your favorite NBC News Shows. Connect with NBC News Online! NBC News App: https://smart.link/5d0cd9df61b80 Breaking News Alerts: https://link.nbcnews.com/join/5cj/breaking-news-signup?cid=sm_npd_nn_yt_bn-clip_190621 Visit NBCNews.Com: http://nbcnews.to/ReadNBC Find NBC News on Facebook: http://nbcnews.to/LikeNBC Follow NBC News on Twitter: http://nbcnews.to/FollowNBC #Ukraine #Russia #Zelenskyy #Putin #Biden NBC News Exclusive: One-On-One With Ukrainian President Zelenskyy