War in the Middle East has upended the world economy, the International Monetary Fund said on Tuesday, warning in a report that disruptions to oil markets could slow growth, fuel inflation and raise the possibility of a global recession.

The sober message came after the global economy had largely weathered a pandemic, Russia’s war in Ukraine and soaring inflation without tipping into a recession. But President Trump’s decision to initiate a war in Iran has stopped the world economy in its tracks.

In its latest World Economic Outlook, the I.M.F. sharply downgraded its growth forecasts, exposing the economic fallout from a geopolitical crisis that has roiled energy prices and injected a new bout of uncertainty into the global economy.

“The global outlook has abruptly darkened following the outbreak of war in the Middle East,” Pierre-Olivier Gourinchas, the I.M.F.’s chief economist, wrote in the report. “The war interrupted what had been a steady growth trajectory.”

The I.M.F. said that even if the war is short-lived, the damage to the global economy has been done. In that best-case scenario, the fund expects global growth to fall to 3.1 percent this year from 3.4 percent in 2025. That is down from the 3.3 percent that the fund projected in January. It is also lower than the 3.4 percent growth that it was prepared to project before the war broke out and oil shipments through the Strait of Hormuz were halted.