LONDON — United States, Portuguese and British authorities are investigating what caused a cargo ship to collide with an oil tanker carrying jet fuel for the U.S. military off the coast of eastern England Monday.

With the fire still blazing, British government minister Matthew Pennycook said Tuesday morning the three governments were working together after the crash set both vessels alight and triggered a major rescue operation.

But he refused to speculate on potential causes, including foul play.