Donald Trump has criticised the Opec oil producers' group, saying crude prices are "artificially very high".
In a tweet, the US President said this was "no good" and "would not be accepted".
The main crude oil benchmark prices, Brent and West Texas Intermediate (WTI), fell around 1% after the tweet.
Oil prices have been rising over the past few months and on Thursday hit their highest levels since November 2014.
Opec and some other oil producing countries have been curbing production in an attempt to push up prices.