Ukrainian President Volodymyr Zelensky has warned all airlines against flying over Russia, saying Ukrainian drone operations would make the country's airspace unsafe.
"Russian airspace is becoming completely unsafe," Zelensky said in a statement on Tuesday evening, adding that Ukraine was not threatening civilian aviation or individual aircraft.
"There will simply be drones in Russia's skies on a scale that has to be taken into account," he said. Russian airspace would be "effectively" closed, he added. Last week, he had threatened the deployment of up to 1,000 long-range drones per day.
Zelensky confirmed media reports that the US had asked for a pause in attacks on Moscow and St Petersburg on the previous Tuesday, Wednesday and Thursday. CIA chief John Ratcliffe travelled to Moscow unannounced during that period.
A further country had also asked for a pause in attacks on Vladivostok, Zelensky said. An economic forum with international guests and an appearance by Russian President Vladimir Putin is taking place in the major Russian Pacific city from Tuesday to Friday.
Ukrainian strikes have not yet taken place in the Far East region, which is more than 6,000 kilometres from Ukraine.
Ukraine has been defending itself against a full-scale Russian invasion for more than four and a half years, repeatedly striking distant targets deep inside Russia with drones as part of its defence effort.