Saudi Arabia reduced crude oil supplies to at least 11 refiners in Asia and most buyers in Europe after the kingdom volunteered to cut its production by 1 million barrels a day for February and March.

Oil traders in Asia are expecting refineries to cut operating rates and extend shutdowns as the spread of coronavirus stops people from flying or traveling by road.

If the United States decides to deploy a slate of sanctions that it is said to have drafted against the Latin American nation, American refiners would be forced to cease purchases. That may mean more supply becomes available for the OPEC producer’s other big customers: China and India.