The Kremlin has denounced Foreign Secretary Boris Johnson's statement comparing the World Cup in Russia to the Olympics hosted by Nazi Germany as "utterly disgusting".
The tough response marks an escalating war of words between Moscow and London over the poisoning in Salisbury of former Russian spy Sergei Skripal and his daughter with a military-grade nerve agent.
Britain blamed the attack on Russia, which fiercely denied the accusations.
Mr Johnson agreed on Wednesday with a Labour politician who likened the football World Cup hosted by Russia this summer to Adolf Hitler's use of the 1936 Olympics as propaganda for his regime.
Russia's President Vladimir Putin's spokesman Dmitry Peskov described it as "the utterly disgusting statement which is unworthy of a foreign minister of any country".
He called Mr Johnson's words "insulting and unacceptable".