Russia on Wednesday accused Ukraine of attempting an assassination of President Vladimir Putin, and Kyiv denied involvement.
The Kremlin said Ukraine launched an unmanned aerial vehicle strike against the Kremlin presidential residence on Wednesday, according to Russian media reports.
The strike, what the Kremlin called "a planned terrorist act and an attempt on the life of the President of Russia" in a statement, involved two unmanned aerial vehicles that were shot down by Russian forces. Putin had not been in the Kremlin at the time, according to RIA news agency, and his work would continue as scheduled.
In response, a senior Ukrainian official said that Kyiv had "nothing to do with" any drone attack on the Kremlin.
Ukrainian presidential adviser Mykhailo Podolyak wrote on Twitter that the allegation could indicate Moscow was preparing for "a large-scale" attack against Ukraine in coming days.
"The Russian side reserves the right to take retaliatory measures where and when it sees fit," the Kremlin added.
Earlier on Wednesday, Moscow Mayor Sergei Sobyanin announced a ban on the use of unauthorized civilian drones in the city from May 3.
The Victory Day military parade on Red Square slated for May 9 also remains unchanged, Russian media reported citing Kremlin spokesman Dmitry Peskov in wake of the drone attack.