Brent crude fell 1.3% to $108.40 per barrel, while WTI slipped 0.4% to $112.02, staying under $110.
President Donald Trump warned Iran of strikes on bridges if it fails to reopen Strait of Hormuz by U.S. deadline.
Iranian ambassador to Pakistan Reza Amiri Moghadam said mediation efforts are at a critical, sensitive stage, urging observers to stay tuned.
OPEC+ announced a lift in production targets, but analysts say it is symbolic as Iranian attacks continue hampering output and tightening markets.