The United States is considering returning Cuba to its list of state sponsors of terrorism, a senior Trump administration official told Reuters on Thursday, a move that would mark another major blow to increasingly tense relations between Washington and Havana.

There is a "convincing case” that Cuba should be placed back on the U.S. blacklist, in part because of its continued backing for socialist Venezuelan President Nicolas Maduro and the refuge it gives to leaders of Colombia’s ELN rebel group, the official said.

Speaking on condition of anonymity, the official did not rule out that a decision on Cuba’s re-listing could come by the end of the year.