Russian forces destroyed 20 Ukrainian drones launched onto the Crimean Peninsula early on Saturday, Russia's defense ministry said.
There were no casualties and no damage as a result of the attempted attack, the ministry said on the Telegram messaging app. It said 14 drones were destroyed by air defense systems and six were suppressed by electronic warfare.
Reuters could not independently verify the report.
It was not immediately clear what was targeted in the reported attacks on the Russian-annexed peninsula.
Sergei Kryuchkov, an adviser to the Russia-installed governor of Crimea, said earlier that air defense systems were engaged in repelling air attack in different parts of the peninsula.
Crimea transport authorities said on their Telegram channel that traffic on the Crimean Bridge, which links the Black Sea peninsula with the Russian region of Krasnodar, was suspended for about two hours from 1:30 a.m. (2230 GMT).
Drone attack increasing in Russian-controlled territories
Drone attacks on Russian-controlled territories in Ukraine and deep inside Russia have increased since a drone was destroyed over the Kremlin in early May.
Ukraine almost never publicly claims responsibility for the attacks but has said destroying Russia's military infrastructure is crucial for Kyiv's counteroffensive.
Moscow annexed Crimea from Ukraine in 2014, eight years before President Vladimir Putin ordered the full-scale invasion of Russia's neighbor in February last year.
Russia's Defense Ministry said that Ukraine had tried unsuccessfully to strike the Crimea Bridge with S-200 rockets, but that no damage or casualties had been caused.
Earlier, Russian-installed Crimea governor Sergei Aksyonov said that two rockets had been downed by anti-aircraft defenses near the bridge, which has come under repeated attack by Ukraine since last year.