The Kremlin on Monday expressed concern after U.S. President Joe Biden called the Russian leader Vladimir Putin a "butcher" over his military operation in Ukraine.
"This is a statement that is certainly alarming," Kremlin spokesman Dmitry Peskov told reporters during his daily press briefing.
"We will continue closely monitoring statements of the U.S. president," Peskov added.
During a visit to Poland on Saturday, Biden dubbed Putin "a butcher" who "cannot remain in power."
The White House later scrambled to deny he was seeking "regime change" in Moscow, while the Kremlin said Biden's words could harm bilateral relations.