Trump took to Twitter to bash OPEC over its artificially high gas prices.

WTI oil prices hit a three-year high above $69 a barrel this week and were still trading above $68 on Friday. The international benchmark, Brent crude, was above $73 on Friday after also hitting its highest level since November 2014 this week.

The president is likely referring to OPEC’s production level agreement with Russia and other producers put in place last year and set to expire at the end of 2018.

There have also been reports lately that Saudi Arabia, the key member of the cartel, wants oil at $80 to $100 a barrel in order to boost the eventual initial public offering of its state oil company, Saudi Aramco.

When asked to comment on Trump’s tweet, Saudi Energy Minister Khalid al-Falih told CNBC, “Markets should determine price.”

The claim from the Saudi energy minister doesn’t hold much weight. A free market allows the market to set the price of goods. What they are doing is clearly setting the price at between $80-100 which is price fixing.