( dpa )- A Ukrainian helicopter crashed in the Black Sea on Thursday killing twelve and leaving only one survivor, officials at Ukraine's Border Troops command said.
It happened in the north-western Black Sea, near the mouth of the Danube River.
A total 13 persons, 3 flight crew and 10 passengers, had been aboard the aircraft at the time of the crash. Eleven of the dead were border security staff, and other person killed was a civilian.
The identity of the single survivor was not immediately made public.
The Ukrainian border troops Mi-8 helicopter had been carrying personnel and two tonnes of supplies to Zmeyniy Island, a rocky outcrop claimed by some 60 kilometres south of the Danube's mouth.
The flight from the mainland to Zmeyniy Island by Mi-8 lasts approximately 45 minutes. It was not clear when exactly, or for what reason, the helicopter had crashed.
The downed helicopter was visible in shallow water, and had apparently almost reached the island before hitting the water, witnesses said.
Two motor launches and a pair of helicopters participated in a search of the area.
One of the helicopters carried the single survivor to a hospital in Ukraine's Odesa province, where he was being treated for multiple injuries and listed in "very serious condition."
Ukraine has seen unsettled weather in recent days, with snows even in lowlands and temperatures hovering slightly above freezing, alternating with sunny weather from 10-13 degrees centigrade.
Zmeyniy Island is the site of a Border Troops station maintained by Ukraine on the 1.5 square kilometre rock to buttress a Kiev claim to territorial waters in the region.
Neighbouring Romania says the claim is baseless and the border troops installation meaningless, as Zemyniy Island has always been uninhabited.