The Iran war has brought shipping through the Strait of Hormuz, where normally a fifth of the world's oil passes, to an almost complete halt.
A source with knowledge says that Kuwait, which produced 2.8 million barrels per day last year, reduced production by 100,000 barrels per day on Saturday and that Sunday's reduction will almost triple.
This will be followed by several reductions, depending on storage options and the location in the strait.
The United Arab Emirates, the third-largest producer in the OPEC+ oil group, will also reduce production.
Saudi Arabia, Iraq and Qatar have already reduced output.
