Oil prices remained near six-week highs on Monday after tit-for-tat U.S.-Iran strikes on vessels kept crude flows through the Middle East constrained. Brent crude futures were down 9 cents, or 0.1%, at $96.19 a barrel at 0822 GMT after reaching $97.93, their highest level since July 24. West Texas Intermediate was down 45 cents at $91.03. Brent gained about 8% last week and WTI nearly 10% after the attacks resumed, leaving crude nearly 40% above prewar levels. U.S. forces struck three Iranian oil tankers on Saturday, including one near Kharg Island, while Iran's Islamic Revolutionary Guard Corps said it targeted three tankers using unauthorized routes through the Strait of Hormuz and three additional U.S. vessels. Commodity tanker traffic averaged just 10 ships a day through the strait over the previous 10 days, the lowest level since May. Goldman Sachs said oil could reach $120 a barrel if attacks on shipping intensify. Iran said it would announce a restricted zone outside the strait in coming days, while OPEC+ left its October output policy unchanged. Earlier supply concerns included Iran's reported progress with Oman on a tanker route, U.S. naval and blockade policies, declining U.S. Strategic Petroleum Reserve inventories, and lower Chinese crude imports and refinery runs.