Celsius Roskilde, formerly Alpine Eternity, is a Marshall Islands-registered oil and chemical tanker.

[2] When the ship's master refused, the patrol boats fired shots across the bow of the vessel, at which point the tanker shifted course to the territorial waters of the United Arab Emirates (UAE).

The patrol boats then fired directly upon the tanker in attempt to disable her.

[2] The following day, an Iranian official said that Iran had attempted to seize Alpine Eternity because she had hit an Iranian oil rig on 22 March 2015, doing $300 million in damage, and the vessel's operator, Transpetrol, had not taken steps to pay compensation.

Singapore, the country to which the vessel was registered, condemned Iran's action as "a serious violation of international law".