A Moroccan man has described how the Algerian coastguard opened fire on him and three other tourists who had strayed into Algerian waters.
Mohamed Kissi was the only survivor to make it back. His brother and a friend were killed and another friend is said to be in Algerian custody.
“They charged, then began to shoot behind us,” Mr Kissi told French television network BFM.
Morocco has opened an investigation and there has been no comment from Algeria.
The two nations have a long history of tension, tied to Morocco’s claims to the disputed territory of Western Sahara.