Explosions were heard near the bridge linking Russian-occupied Crimea to the Russian mainland early on Saturday, Russian-appointed officials reported, saying the blasts were linked to a Ukrainian drone attack on a Russian tanker.

Russia’s sea rescue service in the Black Sea port of Novorossiysk said tugboats were dispatched to help the tanker, which was damaged and unable to operate on its own.

“We can say that the tanker is damaged in the (Kerch) strait, only on the south side,” Russia’s Tass news agency quoted the rescue centre as saying.

“They will deal with it now on whether to take it under tow or not. It is standing at anchor for the moment. The machine room suffered some damage, not too badly.”

Overnight a Russian warship was seriously damaged in a Ukrainian naval drone attack on Russia’s navy base at Novorossiysk, the first time the Ukrainian navy has projected its power so far from the country’s shores.

Russia-installed officials in the Crimea peninsula, annexed by Moscow in 2014, said the latest explosions had nothing to do with the bridge, which has come under serious attack twice in the 17-month-old Russian invasion of Ukraine.

Ukraine, which rarely comments on attacks on Russian targets, made no official statement on the incident.

Traffic was halted for a time on the bridge, the third such stop in the past 24 hours, but later resumed.

“Once again, there was no direct attack on the Crimea bridge and there was no explosion in the immediate vicinity,” Oleg Kryuchkov, an adviser to the Russia-installed governor of Crimea, was quoted as saying by Russian news agencies.

Ukraine’s UNIAN news agency said three explosions had been reported in the area.

Ukrainian news reports and pro-Russian officials in occupied parts of Ukraine said Ukrainian drones had attacked a tanker vessel in the Kerch Strait operating under a Russian flag and identified as the SIG.

One Russian-appointed official in Ukraine’s southeastern region of Zaporizhzhia, Vladimir Rogov, posted an audio clip in which the vessel had requested a tow from tugboats.

Rogov, writing on the Telegram messaging app, posted pictures of what he described as shattered fixtures and equipment inside the vessels.

The ship, he said, had been supplying oil to Russian troops in Syria.

The bridge, completed by Russia in 2018, four years after Moscow annexed the peninsula from Ukraine, has been subjected to two major attacks in the 17-month-old Russian invasion of Ukraine, with the most recent one occurring last month.

Ukraine has claimed responsibility for the attacks only indirectly.