A senior aide to U.S. President Joe Biden has warned against "steps that could inadvertently punish innocent Russians" following a European Union move to tighten visa rules for Russian tourists. In his first broadcast interview since his appointment last year, Rob Berschinski, special assistant to the president, also said the United States was financing organizations gathering evidence of Russian war crimes in Ukraine. Berschinski, who is also senior director for human rights on the National Security Council, spoke to RFE/RL's Ray Furlong in Prague on August 31.