Hamas has claimed to have captured an Israeli 'killer dolphin' spy armed with 'weapons capable of assassinating' its fighters off the coast of Gaza.  

A video posted online by the Palestinian organisation's military wing claimed one of its naval combat units had discovered and captured the hostile aquatic operative while at sea.

It said the naval unit was chased by the alleged Israeli intelligence agent, which was wearing a harness equipped with weapons capable of 'assassinating' Hamas fighters. 

Spokesperson Abu Hamza said in the video that the dolphin was found by one of the group's fighters. 

Israel has a fleet of 'Dolphin-class' submarines but Hamas's video made it clear that the group was referring to the mammal and not the boats. 

They showed footage of a harness, allegedly taken from the captured spy, which was loaded with a spear gun-like weapon - but looked similar to devices used in US, Russian and Ukrainian naval marine experiments. 

Israel has not responded to the allegations. 

The alleged harness was conical and could have been attached to the dolphin's snout - similar to harnesses used by US, Ukrainian and Russian naval marine programs, according to defence analyst H I Sutton.