The Ukrainian soldiers reported dead on a small Black Sea island who Kyiv planned to posthumously honor are said to be "alive and well" after being captured by Russian troops, the Ukrainian navy announced Monday.

"We are very happy to learn that our comrades-in-arms are alive and well," the navy said on Facebook. The Ukrainian soldiers had surrendered after running out of ammunition, it said. Russia destroyed the entire infrastructure of the island.

The chaotic information environment surrounding the invasion led to confusing and sometimes contradictory accounts. Kyiv assumed the 13 soldiers were dead after it lost connection with the island. Border guards, who were caught telling the Russian asking them over the radio to surrender to "go f*** yourself," were reported to have been killed while defending the island, authorities said Friday, adding that the soldiers would be posthumously honored for their bravery.

However, the Russian military shared pictures of the prisoners and Russian state TV later showed what it claimed was footage of the soldiers alive in custody.

In an audio clip shared online, a soldier from a Russian military ship can be heard telling the Ukrainian guards on the island to "lay down your arms immediately to avoid bloodshed and unjustified deaths," adding "otherwise you will be bombed."

After a brief discussion among themselves, the guards respond by saying: "Russian warship, go f*** yourself."

The recording of the exchange between Ukrainian and Russian forces has been circulated by a Ukrainian official and the media outlet Ukrainskaya Pravda.

Russian forces launched a full-scale invasion in the early hours of Thursday, which is thought to be Moscow's most aggressive action since the Soviet invasion of Afghanistan in 1979.