Moscow - A senior Russian diplomat is expected to hold talks at Britain's foreign ministry on Thursday after Prince Charles reportedly compared President Vladimir Putin's actions to those of Adolf Hitler, a government source said.
The heir to the British throne made the apparently unguarded comment during a trip to a museum in Canada, in private conversation with a Polish-born woman who had fled the Nazis as a child.
Moscow has not formally commented but Russian media said it threatened to further “complicate” relations between Britain and Moscow, already tense over the crisis in Ukraine.
A British government official told AFP that “it's likely that the Russian deputy ambassador will come in later today” to the Foreign Office over the comments.
There was no immediate comment from the Russian embassy in London.
Charles and Putin are both attending commemorations marking the 70th anniversary of D-Day on June 6, although royal aides said no formal meeting was scheduled.
The 65-year-old British royal's comments were reported by the Daily Mail newspaper on Wednesday.
“I had finished showing him the exhibit and talked with him about my own family background and how I came to Canada,” 78-year-old Marienne Ferguson told the paper.
“The prince then said: 'And now Putin is doing just about the same as Hitler'.”
The leaders of Britain's three main political parties - Conservative Prime Minister David Cameron, Liberal Democrat Deputy Prime Minister Nick Clegg and Labour leader Ed Miliband - all backed Charles's right to express private views despite his role as future head of state.
Miliband even said that Charles “has got a point about President Putin's actions”.
The prince's office would not confirm the remarks, but said he would not have intended to make a political statement.
Ties between London and Moscow were plunged into a deep freeze following the 2006 murder of Alexander Litvinenko, a Russian dissident, in London.
Relations began to improve in 2011, but the crisis over Ukraine has led to fresh tensions as the United States and the EU imposed sanctions on Russia for its intervention in the former Soviet state.