Oil futures ended with a loss on Thursday after President Donald Trump in a tweet called for the Organization of the Petroleum Exporting Countries to maintain lower crude-oil prices.

“We protect the countries of the Middle East, they would not be safe for very long without us, and yet they continue to push for higher and higher oil prices! We will remember. The OPEC monopoly must get prices down now!” Trump tweeted on Thursday.

October West Texas Intermediate crude US:CLV8 lost 32 cents, or nearly 0.5%, to settle at $70.80 a barrel on the New York Mercantile Exchange. The U.S. benchmark contract on Wednesday closed at the highest for a front-month contract since July 10, according to FactSet data. The October contract expired at the end of session. November WTI crude US:CLX8 which became the front month, shed 45 cents, or 0.6%, to settle at $70.32.

Global benchmark November Brent UK:LCOX8, meanwhile, fell 70 cents, or 0.9%, to finish at $78.70 a barrel on ICE Futures Europe, pulling back from an intraday high of $79.83.

Trump’s comments came ahead of a closely watched meeting in Algiers of a committee made up of representatives of OPEC members and its outside allies on Sept. 23. The producers had agreed in June to boost production in an effort to get output nearer a previously agreed ceiling. The June agreement was seen, in part, as a response to U.S. pressure.

Oil prices have been on the rise, boosted in part by Trump’s decision to pull out of the Tehran nuclear accord and renew sanctions on Iran aimed at sharply curtailing the major producer’s exports.

Trump’s latest tweet also came after a news report earlier this week said officials from Saudi Arabia, OPEC’s de facto leader and the crucial swing producer, were growing comfortable with the possibility of crude prices above $80 a barrel.

“The U.S. is keen to avoid the fallout from Iran sanctions,” said Fiona Cincotta, senior market analyst at City Index. U.S. representatives have in separate negotiations asked the two of the largest producers, Saudi Arabia and Russia, “to keep production levels up in order to avoid a spike in prices.”

Still, an upward tilt for U.S. oil has been underpinned by data showing declines in supplies. The Energy Information Administration’s report on Wednesday indicated that U.S. crude supplies fell by 2.1 million barrels for the week ended Sept. 14. That marked a fifth straight weekly decline.

Gains in crude also have been supported by expectations for supply disruptions in the Middle East that could drive prices higher, even as OPEC and major oil producer Russia attempt to pre-empt expected global declines from Iran.

The Trump administration in May decided to pull out of a nuclear agreement with Tehran and impose sanctions on the country targeting oil in early November that are estimated to decrease Iranian output by 1.4 million barrels a day, according to S&P Global Platts Analytics.

Back on Nymex, prices for petroleum products finished lower along with oil. October US:RBV8 declined by 0.3% to $2.015 a gallon and October heating oil US:HOV8 fell 0.8% to $2.228 a gallon.

October natural gas US:NGV18 rose 2.3% to settle at $2.976 per million British thermal units after a report from the EIA Thursday showed that U.S. supplies of the commodity rose generally within market expectations last week.

Domestic supplies of natural gas climbed by 86 billion cubic feet for the week ended Sept. 14, the EIA said. Analysts polled by S&P Global Platts had forecast a climb of 83 billion.