Oil prices edged higher during Asian trading on Friday after the United States threatened to maintain an indefinite naval blockade of Iran, reviving concerns over crude supply following a decline in the previous session.
By 3:05 pm AEST (5:05 am GMT), Brent crude futures had risen 6 cents, or 0.1%, to US$87.13 per barrel, while U.S. West Texas Intermediate (WTI) crude futures gained 10 cents, or 0.1%, to $81.35 per barrel.
Both benchmarks were on track for weekly gains, with Brent up 4.3% and WTI 4.1%.
The U.S. warned on Thursday that it could maintain a naval blockade of Iran indefinitely and increase economic pressure on Tehran as ceasefire negotiations have stalled.
"Watch this space for more announcements coming next week because we are going to apply measures like have never been seen in the history of economic isolation of a country," Treasury Secretary Scott Bessent told Newsmax's "Rob Schmitt Tonight" programme in an interview.
The latest threats came as Iran continued to restrict traffic through the Strait of Hormuz, a critical shipping route that carried around 20% of global oil supplies before the conflict.
The disruption has pushed up fuel prices and increased pressure on President Donald Trump to end the war, which has become unpopular domestically.
Concerns over a prolonged conflict and tighter crude supplies were partly offset this week by the International Energy Agency and OPEC lowering their forecasts for oil demand growth.
U.S. data also showed the country's largest weekly increase in crude inventories in more than three and a half years.
Meanwhile, two vessels operated by state-owned Abu Dhabi National Oil Company were reportedly attacked while transiting the Strait of Hormuz on Thursday, according to UAE state news agency WAM. The United Arab Emirates government condemned the incident as an Iranian attack.
