Russia was warned, Putin said the "special military operation" in Ukraine was what mattered, dismissing the warning
The 7 March warning from the US to its own citizens was unusually specific. It talked of reports that "extremists" had "imminent plans to target large gatherings in Moscow" and specifically mentioned concerts. It advised Americans in the city to avoid large gatherings over the coming 48 hours.
Three days before the attack, Russian President Vladimir Putin addressed the board of Russia's Federal Security Service (FSB), whose job is to defend the country. The top priority, he told the assembled leaders of the security service, was to support what he called the special military operation - the official phrase for the full-scale invasion of Ukraine.
He claimed that Ukraine had switched to what he called "terrorist tactics". He also spoke directly to what he said were "provocative statements" from the West about potential attacks within Russia. He said the warnings "resemble outright blackmail and the intention to intimidate and destabilise our society".
That suggests that the mistrust between the US and Russia meant Moscow may not have wanted to listen and instead saw the warnings as part of an attempt to threaten Russia, linked to the Ukraine conflict.
https://www.bbc.com/news/world-europe-68646375
= new reply since forum marked as read
Good thing we aren't likely to have that happen in OUR country. 
(which is most likely a plot too)
