Oil climbed after the US attacked Iranian tankers and Tehran declared a new restricted zone outside the Strait of Hormuz, raising concerns about prolonged disruptions to energy flows. Brent gained as much as 0.8% to trade near $97 a barrel at the open, while West Texas Intermediate was around $92.

The US said it launched strikes against three Iranian oil tankers over the weekend, destroying one, in retaliation for attacks on American Navy warships with ballistic missiles. In response, Iran's top security official said a new restricted zone outside of Hormuz will be declared in the coming days, beginning at the US Navy blockade line and extending into parts of the Persian Gulf, Press TV reported. Iran also said it targeted three tankers, but there was no independent corroboration.

Crude surged last week after hostilities flared between the US and Iran after a period of relative calm. Brent crude is up almost 60% this year, with refined products such as diesel seeing even steeper gains due to the Middle East conflict and the Russia-Iran war. US Energy Secretary Chris Wright said there won't be any letup in the US naval presence, which includes the blockade to stymie Iranian oil exports as well as helping to ensure safe passage for other commercial ships through the strait.