Selena Gomez and Justin BieberSelena Gomez has so far denied any relationship, other than a platonic one, with Justin Bieber. But she's going to have a hard time explaining the most recent images to surface of the rumored couple.

Bauer Griffin has a set of pictures that show the couple kissing aboard a luxury yacht in the Caribbean, where they were vacationing with friends.

One photo appears to show Gomez, 18, draping her arms over Bieber, 16, while another shows the two kissing. In another image, Bieber looks to have his hand on Gomez's butt as they leave the yacht's deck.

The Daily Mail reports that Bieber's fans had posted several threatening tweets to the Disney star when the news broke out. One message read, "Roses are red, violets are blue, @selenagomez if you'll break @justinbieber's heart I'm gonna kill you."