Brent crude futures fell 66 cents, or 0.65%, to $101.59 a barrel, while U.S. West Texas Intermediate crude dropped 95 cents, or 1.03%, to $90.12 a barrel.
Brent gave up most of its gains from last week, while WTI fell 1.6%.
According to Reuters, the declines came after Group of Seven countries agreed to release 100 million barrels of diesel and crude oil from strategic reserves and pledged to refrain from restricting energy exports, a decision made under pressure from U.S. President Donald Trump.
The additional supplies will add to Middle East oil exports, which exceeded prewar levels on four of the final seven days of September, according to shipping data released Monday, despite attacks on vessels transiting the Strait of Hormuz.
“The G7 decision to tap strategic reserves eases some of the price pressure caused by concerns over supply shortages. At the same time, confidence is growing that Saudi Arabian export volumes are returning to prewar levels, even if that oil is being transported at higher costs and via less efficient routes,” said Tim Waterer, chief market analyst at KCM Trade.
As previously reported, Trump said July 22 that every time Iran attacked a vessel in the Strait of Hormuz, the United States would destroy a bridge or power plant.
On the night of July 23, U.S. forces carried out their 12th consecutive night of attacks on Iran.
Oil prices rose July 23 to their highest level in more than six weeks as tensions escalated in the Red Sea and the United States launched further strikes on Iran.
On July 28, U.S.-Iran talks affected oil prices.
Oil prices fell July 30 despite renewed escalation in the Middle East.
On Aug. 3, a statement by Trump sent oil prices sharply lower.
Oil prices rose Aug. 10 amid uncertainty over the reopening of the Strait of Hormuz.
On Aug. 17, tensions between the United States and Iran moved oil prices higher.
Oil prices edged lower Aug. 21 despite the prospect of a second consecutive weekly gain, as the deadlocked U.S.-Iran war continued to disrupt supplies from the key oil-producing region of the Middle East.
Oil prices continued to fall Aug. 27 on expectations that talks between Iran and Oman could help lead to the reopening of the Strait of Hormuz.
On Sept. 10, oil prices topped $100 a barrel.
Oil prices edged higher Sept. 28 as ceasefire talks between the United States and Iran were delayed after Trump rejected a proposed peace agreement.