(CNN) The Ukrainian defenders of Snake Island -- who were all feared dead after their defiant response to threats from a Russian warship -- are actually "alive and well," according to the Ukrainian Navy.
All of the soldiers on the tiny island in the Black Sea were thought to have been killed in an attack on the first day of Russia's invasion of Ukraine last Thursday.
According to a purported audio exchange, one of the Ukrainian troops had responded to a warning from an approaching Russian vessel to lay down their weapons or face bombing by saying, "Russian warship, go f*** yourself."
Ukrainian President Volodymyr Zelensky said later on Thursday that 13 soldiers on Snake Island all died "heroically" by Russian bombardment. But -- after the Ukrainian border guard said that it had information disputing the deaths -- a statement on Monday from the country's navy suggested this was certainly not the case.
According to the navy the soldiers on the island repelled two attacks by Russian forces but in the end were forced to surrender "due to the lack of ammunition."
The statement added that Russian attackers have completely destroyed the island's infrastructure, including lighthouses, towers and antennas.
Russian state media also showed the arrival of the Ukrainian soldiers in Sevastopol, Crimea where they are being held.
Snake Island, also known as Zmiinyi Island, sits about 30 miles (48 kilometers) off the southern tip of the Ukrainian mainland in the northwestern Black Sea. It's about 185 miles west of Crimea, the Ukrainian territory that Russia annexed in 2014.
Though it is only about 46 acres (18 hectares) in size, a report last year from the non-partisan Atlantic Council think tank called it "key to Ukraine's maritime territorial claims" in the Black Sea.
Highlighting its strategic importance, Zelensky chose Snake Island last year as the spot for an interview with Ukrainian media in advance of a summit to try to reverse Russia's annexation of Crimea, the Atlantic Council report said.