The Organization of the Petroleum Exporting Countries announced Friday that its members and some non-member countries—namely Russia—will drastically cut oil production in 2019 despite pressure from President Donald Trump. The decision comes at the end of a marathon round of negotiations in which Saudi Arabia—the largest exporter of petroleum—insisted on Russia joining in on meetings. The cut is intended to end a global oil supply glut that has lowered oil prices across the board. The United States recently became a net oil exporter, and President Trump has been pushing U.S. ally Saudi Arabia not to drive prices upward. OPEC, along with Russia and its allies, will curb oil output by a collective 1.2 million barrels a day for six months beginning in January. The OPEC announcement caused oil prices to spike Friday morning.