British Prime Minister Rishi Sunak and Defense Secretary Grant Shapps were alerted in a secret briefing earlier this month that the Russian nuclear submarine Kazan had been spotted off the coast of Scotland en route to Cuba.

The officials were alerted on June 5 that the Russian Yasen-class submarine was detected after an RAF surveillance plan trailed it near the west coast of Ireland to Scotland, reported the Daily Mail.

Kazan, a 13,800-ton submarine, went past the British nuclear naval base in Faslane but did not cross into British waters, eventually making its way to Havana, Cuba, for a stopover that the United States and Cuba said posed no threat but had been seen as a show of force by Russia in connection with the war in Ukraine.

Kremlin spokesman Dmitry Peskov said the submarine movement "is a normal practice for all states, including such a large maritime power as Russia, so we don't see any reason to worry in this case." 

The Kazan and other Russian ships arriving in Cuba carried no nuclear weapons, according to U.S. and Cuban officials. 

The Express in London, first reporting that the prime minister had been briefed, noted that the move comes as President Vladimir Putin vowed to punish Ukraine's Western allies for loaning the country billions of dollars through frozen Russian assets and for giving Ukraine long-range missiles. 

The Kazan and other Russian ships were expected to continue traveling to Venezuela and Guyana, where the Royal Navy patrol ship HMS Trent had been deployed as a show of support against increasing tensions from Venezuela.

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