Sea drone zeroes in on a Russian tanker in the Black Sea (Image: UGC/AP) The attack on a Russian SIG chemical and oil tanker in the Black Sea is showing Moscow that ‘nowhere is safe for its forces’, experts said. A sea drone carrying up to 1,000lbs of dynamite damaged the fuel-laden tanker near the Kerch Bridge, linking Russia to the annexed peninsula of Crimea. The vessel used is believed to have been a modified jet-ski, part of an arsenal of vessels transformed into remote-controlled bombs by Ukrainian marine engineers. It came a day after another maritime drone crippled the Olenegorsky Gornyak landing ship at the Novorossiysk naval base. Its loss may affect efforts to resupply forces in occupied southern Ukraine . Ukraine has launched at least 11 sea drone attacks over the past year. In April 2022, the Sunday Express revealed how it had converted at least 40 civilian craft into sea drones, ostensibly to sink vessels invading Odesa. Since then, their use has expanded and designs have become more far-ranging. Most are the size of a small canoe and their fibreglass construction make them difficult to detect. Last month a new range was unveiled, including a modified Kawasaki STX jet ski. Converted jet skis are also believed to have been used on July 16 in an attack on the Russian naval base at Sevastopol and on July 17 against the Kerch Bridge. Kyiv seldom claims responsibility for attacks inside Russia or on Russian-controlled territory in Ukraine . But it has said that destroying military infrastructure boosts its chances of a successful counter-offensive. Ukraine troops preparing drone technology (Image: Getty) While Vasyl Malyuk, head of Ukraine ‘s SBU security service, did not directly admit that Ukraine had attacked the vessel, he commented that any incident with Russian ships or the Crimean bridge is ‘a logical and efficient step towards the enemy’. He added: ‘Moreover, such special operations are conducted in the territorial waters of Ukraine and are completely legal.’ Experts said that smaller vessels are being targeted, as larger warships have adequate defences to prevent attacks. ‘But this is not to say this method isn’t highly effective,’ said Justin Crump, of the Sibylline strategic risk group. ‘ Russia is imposing a blockade on grain supplies and suggesting it controls the Black Sea. Yet it is difficult to hold on to this narrative when you have had two ships sunk or seriously disabled in just two days. ‘ Ukraine is showing Russia nowhere is safe from its forces. Though it won’t affect the overall direction of the war by itself, it is playing a part by making Russia increasingly uncomfortable.’ Last night US Ambassador James O’Brien, head of the State Department’s Sanctions Office, vowed that Russia would never be allowed permanent control of the Black Sea. He said: ‘We cannot allow Russia to have a stranglehold. ‘They have tried it before and will not succeed in this case.’ He said Russia ‘s decision to break a UN-brokered Black Sea grain initiative is losing Moscow support from developing nations: ‘I was at the UN food systems summit in Rome last month. As we were talking about food insecurity, Russia was bombing grain silos and ports in Ukraine . ‘ Ukraine had been one for the world’s bread baskets. Russia recently destroyed 220,000 tonnes of grain waiting to be shipped to the poorest countries. ‘ Ukraine would have exported at least 50 million tonnes had it not been for the blockade – that is what Russia is keeping from people.’