Some of the top U.S. oil refiners are throttling back operations at their facilities this quarter, adding to concerns that a global glut of crude is forming.

The Biden administration will likely need to tap oil from the country’s emergency reserves to counter a spike in gasoline prices and amid inflation fears during the summer driving season.

A fleet of tankers laden with Russian diesel heading to the U.S. East Coast may help to alleviate the most expensive retail prices for the fuel in seven years.

U.S. inventories of distillates — used as diesel for both transportation and heating oil — are enough to meet just 31.2 days of demand, according to the Energy Information Administration. That’s the tightest it has been for this time of the year since 2000.

The U.S. Treasury Department levied sanctions on Mexican trading company Libre Abordo SA de CV for buying Venezuelan oil via oil-for-humanitarian-aid agreements with the embattled country.