The adversarial relationship between Washington and Moscow prevented U.S. officials from sharing any information about the plot beyond what was necessary, out of fear Russian authorities might learn their intelligence sources or methods.
The adversarial relationship between Washington and Moscow prevented U.S. officials from sharing any information about the plot beyond what was necessary, out of fear Russian authorities might learn their intelligence sources or methods.
The US publicly said that there was an increased risk in Moscow for the 48 hours following March 7th. Whether they privately said anything more is unknown (neither side is too eager to share).
Indeed, for the 48 hours following March 7th, security at places like Crocus City Hall was ramped up.
Edit: would you like to hazard a guess as to what was happening at Crocus City Hall on March 7th-9th?