U.S. light crude fell $1.15 to a low of $69.22 a barrel and was last at $69.50, down 87 cents.
Brent crude futures have made a firm breach of the descending trendline which has curbed price action previous.
Earlier today, according to the Russian news agency, TASS, Russia's Energy Minister Alexander Novak said that the OPEC and its allies could sign a new long-term cooperation deal when they meet in early December and added that output quotes could remain in place after 2018.
Benchmark Brent crude futures rose 47 cents to $79.53 a barrel, by 1649 (GMT).
Oil futures rose on Wednesday, with Brent reaching $80 a barrel, after a larger-than-expected drop in U.S. crude inventories and as USA sanctions on Iran added to concerns over global oil supply.
Oil traders were also watching the progress of category 4 Hurricane Florence, which is expected to make landfall in the U.S. by Friday.
China has said that it would not stop buying Iranian oil, but Beijing is also said to have agreed not to increase its oil purchases from Iran.
US crude stocks fell 5.3 million barrels in the week to September 7 to 396.2 million barrels, the lowest since February 2015 and about 3 percent below the five-year average for this time of year, the US Energy Information Administration (EIA) said on Wednesday.
Outside the United States, traders have been focusing on the impact of US sanctions against Iran that will target oil exports from November. This comes amid the Iranian oil sanctions which are set to be imposed on November 4th, while the United States have also demanded nations to drop Iranian imports to zero.
The International Energy Agency said on Thursday that although the oil market was tightening at the moment and world oil demand would soon reach 100 million barrels per day (bpd), global economic risks were mounting.
S&P global Platts said OPEC, in a report, indicated demand for the organization's own crude oil in September will be nearly 1 million bpd more than the level produced in August.
"Saudi Arabia, OPEC's largest producer, saw its output rise modestly to 10.40 million bpd, up 38,000 bpd from the previous month, according to secondary sources, S&P Platts reported".
Although the shipment hiatus is unlikely to signal that China has been purposefully scaling back purchases to comply with US pressure to have Iranian oil sales at zero, it could mean that Chinese refiners were looking for better terms for Iranian oil purchases, according to Bloomberg.
That month Russian Federation produced 11.247 million bpd, a post-Soviet Union record-high.