The Kremlin said on Monday that US President Joe Biden's remark that Vladimir Putin "cannot remain in power" was a cause for alarm, a guarded response to the first public call from the United States for an end to Putin's 22-year rule.
"For God's sake, this man cannot remain in power," Biden said on Saturday at the end of a speech to a crowd in Warsaw. He cast Russia's invasion of Ukraine as a battle in a much broader conflict between democracy and autocracy.
The White House tried to clarify Biden's remarks and the US president said on Sunday he had not been publicly calling for regime change in Russia, which has more nuclear warheads than any other power.
Asked about Biden's comment, which received little coverage on Russian state television, Kremlin spokesman Dmitry Peskov said: "This is a statement that is certainly alarming."
"We will continue to track the statements of the US president in the most attentive way," Peskov told reporters.
Putin has not commented publicly on Biden's remark - which comes amid Moscow's biggest confrontation with the West since the end of the Cold War.
In his first live appearance since the remark, Putin was shown on state television on Monday being briefed by Alexander Sergeev, president of the Russian Academy of Sciences, on the accumulation of carbon in molluscs and the use of artificial intelligence to decipher ancient Tibetan manuscripts.
Biden last year cast Putin as "a killer". After that comment, Biden phoned Putin who then said he was satisfied with the US leader's explanation for the remark.
Such a blunt remark from Biden on the need to end Putin's power, however, appeared to breach the norms of US-Russian relations and also, bizarrely, align with the narrative of the former KGB spies who form Putin's closest circle in the Kremlin.
"It is unusual for the president to talk about regime change so bluntly," William Wohlforth, professor of government at Dartmouth College in Hanover, New Hampshire, told Reuters.
"But it wouldn't seem that unusual from the perspective of Putin's propaganda as he often describes that as the goal of US foreign policy," Wohlforth said.
Putin's inner circle, including Security Council chief Nikolai Patrushev, previously head of the powerful Federal Security Service spy agency, has long argued that the United States is plotting a revolution in Russia.
Dmitry Medvedev, who served as president from 2008 to 2012, said on March 23 the world could spiral towards a nuclear dystopia if Washington pressed on with what the Kremlin casts as a long-term plot to destroy Russia.
Medvedev painted a grim picture of a post-Putin Russia, saying it could lead to an unstable leadership in Moscow "with a maximum number of nuclear weapons aimed at targets in the United States and Europe".
Putin, Russia's paramount leader since Boris Yeltsin resigned on the last day of 1999, casts the war in Ukraine as necessary to protect his country's vital interests in the face of a United States he says is bent on world hegemony. He is particularly keen to quash Ukraine's hopes of joining NATO.
Ukraine says it is fighting for its very survival against a Russian imperial-style land grab that has divided the two biggest Eastern Slav peoples.
Biden's remark on ending Putin's rule overshadowed a speech which had a much broader theme: the battle between democracy and autocracy.
That indicates a much longer war, according to Russian aluminum tycoon Oleg Deripaska.
"Now some sort of hellish ideological mobilization is underway from all sides," he said on Sunday.
"It appears all sides are recklessly gearing up for a long-term war that will have tragic consequences for the entire world," said Deripaska, who has been sanctioned by the United States and Britain.
Under constitutional changes approved in 2020, Putin, who turns 70 this year, could seek election for two more six-year terms as president, allowing him to stay in power until 2036.
The Kremlin says Putin is a democratically elected leader and that it is for the Russian people, not Washington, to decide who leads their country.