On Wednesday, U.S. President Donald Trump warned Russia to prepare for missile strikes against its ally Syria, and oil traders took note. Oil prices soared to fresh three-year highs. U.S. WTI ended Wednesday up 2 percent, at $66.45 per barrel, a price not hit since December 3, 2014. As of 2:17 p.m. HK/SIN, the commodity was trading up further, at $67.03 per barrel. Brent crude futures took a similar trajectory, trading at $72.13 per barrel in the early afternoon on Thursday, up 0.10 percent in the session. U.S. oil prices were up approximately 8 percent thus far this week.

Traders are questioning whether Trump’s comments were aimed at Syria only or whether the U.S. military may also target Iran, OPEC’s third largest oil producer, whose nuclear deal with the U.S. is reaching its May 12 deadline. President Trump has made it clear that he remains unsatisfied with the terms of the deal, and the possibility that the U.S. will withdraw from the agreement looms large. If the U.S. drops out, it would likely impose fresh sanctions on Iranian oil and its financial sector. Europe may follow the U.S.’s lead in order to remain in Trump’s good graces, though there have been no confirmations of this intent yet.

Saudi Arabia is also under fire, increasing the pressure on oil markets even further. Its air defense forces have intercepted at least three ballistic missiles by Yemen’s Houthi faction who have publicly claimed to be targeting Saudi Aramco, Saudi Arabia’s national oil producer. Last week the Houthis launched an attack on a Saudi oil tanker. Analysts are concerned that a strike on an oil tanker shows a weakness in the waterways which could put all inventory on the water at risk.

The political unrest in the Middle East buoyed oil prices even as data released by the Energy Information Administration showed that the country’s commercial crude inventories rose by 3.3 million barrels last week. Reuters analysts had predicted a decrease in inventories.