A man claiming to be the leader of the gang that kidnapped 17 American and Canadian missionaries said he would kill the hostages if he does not receive $17 million in ransom.

A Haitian man identifying himself as the leader of the gang that kidnapped a group of American and Canadian missionaries said in a video posted on YouTube on Thursday that he was willing to kill "these Americans" if he does not get what he needs.

The speaker in the video, dressed in a purple suit, is recognizable as the man known in Haiti by the alias Lamo Sanjou, the leader of the 400 Mawozo gang that authorities say is behind the abduction of the missionaries at the weekend.

The sixteen Americans and one Canadian - including five children - were on a trip organized by the Ohio-based Christian Aid Ministries. The missionaries were not present in the video.

Reuters was unable to independently confirm the veracity of the video or when it was made.

"If I don't find what I need, these Americans, I'd rather kill them all, and I'll unload a big gun in the head of each of them," said the man in the video.