Putin challenges Biden to debate after U.S. president calls Russian counterpart a "killer"

• "It seems to me that would be interesting for the people of Russia and for the people of the United States."

The big picture: Russian officials and the Kremlin seethed this week at Biden's comment. But the American president has stood behind the statement, with White House press secretary Jen Psaki saying Thursday that Biden gave a "direct answer to a direct question" on whether Putin was a killer.

• The White House is also promising further retribution against Russia for a series of malign actions, including poisoning Russian activist Alexei Navalny and the SolarWinds cyber attack.
• Russia has recalled its U.S. ambassador, Anatoly Antonov, citing the need to "analyze what needs to be done in the context of relations with the United States," per the New York Times.