Oil prices dropped to the lows of the session after President Donald Trump signaled that the United States and France are close to reaching an agreement to preserve the Iran nuclear deal.
The United States has until May 12 to decide whether to quit a nuclear deal with Iran and reimpose sanctions against the third-largest producer in the Organization of the Petroleum Exporting Countries.
During a press conference on Tuesday with French President Emmanuel Macron, who wants to keep the deal in place, Trump said the he and Macron "could have at least an agreement among ourselves fairly quickly."
"That's something of a surprise to the market, " said John Kilduff, founding partner at energy hedge fund Again Capital. "We were more expectant of the harsh rhetoric he started with than that he would intimate there's a deal."
U.S. West Texas Intermediate crude ended Tuesday's session down 94 cents, or 1.4 percent, to $67.70, falling further from Thursday's three-year high of $69.56.
International benchmark fell 85 cents, or 1.1 percent, to $73.86 by 2:29 p.m. ET.
Brent briefly spiked to a new three-year high at $75.47 after Trump earlier said Iran will have "big problems" if it restarts its nuclear program. Iran accepted limits on that program in 2015 as part of an agreement with world powers, but Trump has threatened to scrap the deal.
"They restart it, they're going to have big problems, bigger than they've ever had before, and you can mark it down," he told reporters during a photo op with Macron.
Stephen Innes, head of trading for Asia-Pacific at futures brokerage OANDA, said new sanctions against Tehran "could push oil prices up as much as $5 per barrel."
Brent has risen to its highest level since OPEC turned its back on curbing output to support prices on Nov. 27, 2014, a move that triggered a battle for market share and helped deepen a collapse to $27 in early 2016.
Oil prices began to recover in 2016 as OPEC discussed a return to market management with the help of Russia and other non-members. A supply-cutting deal started in January 2017 has been deepened by a steep output drop in Venezuela.
"Prices are being driven up by tight supply due to high production outages in Venezuela plus the cuts implemented by OPEC and Russia," said Carsten Fritsch, analyst at Commerzbank. "What is more, demand appears robust."
OPEC's efforts to tighten markets are being led by top exporter Saudi Arabia, where state-controlled oil firm Saudi Aramco is reportedly pushing for higher prices ahead of a partial listing planned for later this year or 2019.
OPEC's supply curtailments and the threat of new sanctions are occurring just as demand in Asia, the world's biggest oil consuming region, has risen to a record as new and expanded refineries start up from China to Vietnam.
One of the few factors that has limited oil prices from surging even more is U.S. production, which has shot up by more than a quarter since mid-2016 to over 10.54 million barrels per day (bpd), taking it past Saudi Arabia's output of around 10 million bpd.
As a result of its rising output, U.S. crude is increasingly appearing on global markets, from Europe to Asia, undermining OPEC's efforts to tighten the market.
The latest U.S. inventory figures are expected to show a 2.6-million-barrel drop in crude stocks. The American Petroleum Institute, an industry group, releases its data at 4:30 p.m. EDT (2030 GMT) on Tuesday, a day before the government's supply report.
— Reuters contributed to this story.