Who are the parties moving the oil price after a political event?

So the past few weeks we have seen a lot of sudden strong oil price movements. I know marketprices are a result of supply and demand but I just wonder who the people are that cause the price changes after another trump tweet or speech.

Do you have oil companies suddenly deciding to produce less (although that seems like a slow process like OPEX making up their minds) or is it oil refineries deciding to order more oil all of a sudden? But I don't see a good motivation for the to do that if consumer demand is relatively stable.

So who are those parties moving the price, how and why?