The market ignores tensions between Americans and Iranians in the Gulf. Oil prices plunged on Wednesday after an unexpected rise in commercial crude reserves in the United States, a sign of concern about the strength of demand.

Commercial crude oil reserves in the United States rose unexpectedly last week, a negative sign for demand. A barrel of Brent North Sea oil for October delivery fell $2.03 or 2.80% to $70.38 in London from the previous day's close. In New York, the American barrel of WTI for the month of September fell 2.41 dollars or 3.41% to 68.15 dollars. In the Gulf, six days after a deadly attack on an oil tanker, the "potential hijacking" of this ship off the United Arab Emirates ended without damage, the British maritime security agency UKMTO announced on Wednesday.