Ukrainian soldiers believed to have died while defending an island after telling a Russian warship to “go fuck yourself”, may still be alive, according to Ukraine’s State Border Guard.

Initial reports said the 13 border guards had died after refusing to surrender Snake Island, which sits 186 miles (300km) west of Crimea, from a Russian air and sea bombardment on Thursday.

In his address after the first day of the Russian invasion, the Ukrainian president, Volodymyr Zelenskiy, announced he would posthumously award all the soldiers the Hero of Ukraine award. “All border guards died heroically but did not give up,” Zelenskiy said.

They had reportedly responded to an officer on board the Russian warship with a defiant: “Russian warship, go fuck yourself” when asked to lay down their weapons.

But in a recent statement posted on Facebook, the State Border Guard Service of Ukraine said: “We [have a] strong belief that all Ukrainian defenders of