Russian-installed authorities in Crimea said that air defense systems went off on the peninsula.
"Air defense systems worked over different regions of Crimea. Please remain calm and trust only trusted sources of information," Oleg Kryuchkov, an adviser to the Russian-appointed head of Crimea, wrote on Telegram.
Earlier in the night, the traffic on the Crimean Bridge was temporarily paused for a little under two hours, but no specific reason for the move was given at the time. The traffic on the bridge has been halted several times following a Ukrainian attack on the site in July.