U.S. crude futures declined more than $1 in early trade on Thursday after an unexpected build in U.S. crude oil inventories last week raised investor concerns about oversupply. U.S. West Texas Intermediate (WTI) crude futures slid $1.

The American Petroleum Institute (API) estimated that crude oil inventories in the United States fell 4.49 million barrels in the week ending May 2

Oil prices dropped Monday, as the Organization of the Petroleum Exporting Countries and its allies agreed to boost output again in June, raising concerns about a potential oversupply at a time when markets are grappling with the uncertainties of a global trade war.

Wall Street is veering lower while oil prices are down more than $2 a barrel as traders bet on a possible U.S.-Iran nuclear deal.

LONDON (Reuters) -Oil prices settled lower on Thursday on expectations for a U.S.-Iran nuclear deal that could result in sanctions being eased and more barrels released onto the global market. Brent crude futures settled down $1.56, or 2.36%, to $64.53 a barrel. U.S. West Texas Intermediate crude futures settled down $1.53, or 2.42%, to $61.62.

The prospect of a nuclear deal between the U.S. and Iran contributed to the biggest daily drop in oil prices so far this month. But the deal, and a subsequent lift in global oil supplies, are not a sure thing.