US National Security Advisor Jake Sullivan told MSNBC that US-Russian relations face "difficult days" because the countries disagree on important issues.

We believe that there are difficult days ahead with Russia, because there are issues on which we have deep disagreements, there are actions to which we need to respond decisively. We also believe that we can work with Russia on key areas, including in the nuclear area, where we extended the New START Treaty for five years a few weeks ago.

Also during the conversation, Sullivan was asked whether it was wrong for Joe Biden to say yes when asked if he thought Russian President Vladimir Putin was a killer. Sullivan said Biden's words were a direct answer to a direct question.

On March 17, ABC aired an interview with Joe Biden, during which the US President was asked whether he considered Vladimir Putin a murderer, and he responded, "Yeah. Yes, I do." A day later, Putin responded with the tease, "Whoever calls names, calls himself one."
Vladimir Putin also suggested that the US President hold a discussion online. Biden said that he and Putin would talk "at some point." The Russian Foreign Ministry reported that the US refused to hold an open discussion between the two presidents.

Biden Adviser Warns of 'Tough Days' in Russia Relations