A GREENPEACE activist trying to free tuna from a commercial fishing net in the Mediterranean was harpooned through the leg by fishermen on a French boat, the environmental group said.
"In a non-violent action, Greenpeace activists in zodiac boats attempted to lower the side of a purse seine net with sand bags to free the fish," said Isabelle Philippe of Greenpeace France.
"At that moment, fishermen violently attacked the activists, harpooning one of them through the leg," she said.
The injured man, a British national identified by the group as Frank Huston, was transferred to a hospital in Malta where he was to undergo surgery on Friday evening (local time).
"His life is not threatened, but he is in serious condition," Ms Philippe said.
The fishing ship, the Jean-Marie Christian VI, was one of several French tuna vessels in the area when the attack occurred in international waters near Malta, she added.