Customers wait to finish filling their cars at a gas station in Bucharest, Romania, Monday. Romania now leads the EU in high diesel costs, with pump prices rising by 7.5 percent in the last seven days. EPA-Yonhap

NEW YORK — Oil prices fell about 5 percent to a three-week low on Monday after U.S. President Donald Trump held off on a fresh attack on Iran in the hope of sealing a quick deal that could boost oil supplies from the Gulf.

Brent futures fell $4.19, or 4.8 percent, to $83.74 a barrel at 12:40 p.m. ET (1640 GMT), while U.S. West Texas Intermediate (WTI) crude fell $4.92, or 5.8 percent, to $79.75. That put Brent on track for its lowest close since July 13 due in part to the start of the less expensive October futures as the front-month after the more expensive September contract expired on Friday. Iran said on Monday there were no talks under way with the United States and no plans for any meetings, contradicting Trump who had cited talks he said would take place that afternoon as justification for calling off attacks.

Over the weekend, Trump repeated a pattern that has emerged throughout the past five months: announcing plans for "massive attacks" on Iran, only to cancel them at the last minute.