President Donald Trump on Tuesday told a gathering of world leaders that OPEC is cheating them, bringing a grievance he has voiced throughout the year on Twitter to the halls of the United Nations headquarters. "OPEC and OPEC nations are as usual ripping off the rest of the world, and I don't like it. Nobody should like it," he said before the U.N. General Assembly in New York City. "We defend many of these nations for nothing, and then they take advantage of us by giving us high oil prices. Not good." Trump's remarks came just days after OPEC, Russia and several other oil producers rebuffed his latest call to tamp down crude prices by boosting output.

President Donald Trump addresses the 73rd session of the General Assembly at the United Nations in New York September 25, 2018. Timothy A. Clary | AFP | Getty Images

The coalition of roughly two dozen exporters has been limiting its output since January 2017 in order to end a punishing oil price downturn that bankrupted hundreds of American oil companies and heaped financial pressure on crude-producing nations. Trump blames that policy for pushing oil futures into a range between about $70 and $80 per barrel and keeping the national average gasoline price anchored near $3 a gallon. To be sure, the alliance cut output more than anticipated due to production problems in countries like Venezuela and Libya. In June, the group agreed to restore some of that output and return to its goal of keeping 1.8 million barrels a day off the market. However, Trump's decision in May to pull out of the 2015 Iran nuclear deal and restore sanctions on that country, OPEC's third-biggest producer, is also a major factor behind this year's rally.