The accusation comes hours before Russian President Vladimir Putin is due to oversee Navy Day celebrations in his native St Petersburg and endorse Russia’s naval doctrine as Moscow continues its military intervention in Ukraine. “An unknown object flew into the yard of the fleet headquarters,” Mikhail Razvozayev, governor of Sevastopol, home of Russia’s Black Sea Fleet, wrote on the Telegram messaging app. “According to the first information it is a drone.” He said Ukraine decided to “spoil Navy Day for us.” Ukraine’s defense ministry did not immediately respond to a request for comment. Razvozayev said five employees of the fleet headquarters were injured in the incident and that the Federal Security Service (FSB) was investigating his circumstances. “All celebrations have been canceled for security reasons,” Razvozayev said. “Please stay calm and stay home if possible.” Navy Day is an annual Russian holiday in which its fleets hold naval parades and honor its sailors. Russia annexed Crimea from Ukraine in March 2014, sparking a major row with the West that has deepened over Moscow’s role in a pro-Russian separatist insurgency in eastern Ukraine. (Reporting by Reuters; Editing by Kirsten Donovan)