As the Biden administration ponders the path ahead in its strained relationship with Riyadh over oil production cuts, the Saudi energy minister has warned that decisions by some to use emergency oil stocks “may become painful in the months to come.”

Abdulaziz bin Salman said that “people” were using emergency oil reserves to manipulate markets rather than their intended purpose of mitigating shortages of supply.

In a further apparent swipe at the United States, he insinuated that the U.S. reaction to the October 5 decision by OPEC+ to reduce oil production by two million barrels a day had been an immature one.

The comments by the minister, at a major investment forum in Riyadh with a number of Americans present, are a further sign that the kingdom is not backing down in the dispute with one of its most important and longstanding allies.