LONDON—Saudi Arabia on Tuesday reaffirmed its commitment to an OPEC+ agreement with Russia in the oil markets despite widening sanctions on Moscow and global outrage over its military assault on Ukraine. The Organization of the Petroleum Exporting Countries and its allies led by Russia—a group known as OPEC+—have been unwinding historic production cuts they instated in 2020 after the pandemic caused an unprecedented fall in global demand. Then, former U.S. President Donald Trump intervened to encourage Riyadh and Moscow to end a price war and work together to shore up the oil market. Oil prices have rallied to their highest levels in over seven years this week on tight supply and disruptions to crude exports from Russia caused by wide-ranging sanctions on Moscow. Members of the International Energy Agency (IEA) who met on Tuesday to discuss the Ukraine crisis, agreed to release 60 million barrels of oil from strategic reserves. …