The U.S. has seized a sanctioned oil tanker off the coast of Venezuela, President Donald Trump said on Wednesday, a move that sent oil prices higher and sharply escalated tensions between Washington and Caracas.

In response, the Venezuelan government, in a statement, accused the U.S. of “blatant theft” and described the seizure as “an act of international piracy”. It said it would denounce the incident before international bodies.

Trump has repeatedly raised the possibility of U.S. military intervention in Venezuela. The seizure is the first of a Venezuelan oil cargo amid U.S. sanctions that have been in force since 2019. It is also the Trump administration’s first known action against a Venezuela-related tanker since he ordered a massive military buildup in the region.

The U.S. has already carried out several strikes against suspected drug vessels, which have raised concerns among lawmakers and legal experts.