The oil complex was lower in US morning trading Monday, pulling back from last week when a rally lifted crude futures to highs last seen in late January when front-month contracts reached three-year highs.
At 1439 GMT, NYMEX May crude was 31 cents lower at $65.57/b. ICE May Brent was 28 cents lower at $70.17/b.
NYMEX April ULSD was down 31 points at $2.0153/gal. NYMEX April RBOB was 1.61 cents lower at $2.0175/gal.
Tightening US petroleum inventories and turnover in US foreign policy posts provided bullish catalysts last week.
President Donald Trump's appointment of John Bolton as his new national security adviser, along with the firing of Rex Tillerson as US Secretary of State, raise the odds of a US exit from the Iran nuclear deal next month, according to analysts.
"Will we get the same loss of Iranian exports on a unilateral [US] move compared to a multilateral deal on sanctions, possibly not, but it adds to the uncertainty," senior oil analyst at BNP Paribas Harry Tchilinguirian said.
Trump faces a May 12 deadline for the US to waive oil-related sanctions on Tehran as part of the Joint Comprehensive Plan of Action.
"At the end of the day, we feel that excess geopolitical risk premium has been injected into the market and that much of this pop in risk appetite could easily be erased during the next few weeks," consultant Jim Ritterbusch said.
"But we also concede that the geopolitical risk premium has improved the crude chart picture while enticing the money managers back into the long side of both WTI and Brent in potentially setting both markets up for another round of record length," he said in a note.
Trading began Monday in a crude oil futures contract listed on the Shanghai International Energy Exchange (INE), part of the Chinese government's efforts to establish a benchmark closer to home.
The front-month September contract closed at Yuan 429.9/b ($68.03/b), which was 3% higher than at the open.
At 3 pm in Singapore (0700 GMT), Shanghai September crude was $4.06 above NYMEX September crude in electronic trading and 26 cents lower than ICE September Brent.
The September contract attracted the bulk of liquidity. Total volume equaled 42,336 lots, of which 40,656 lots changed hands for the September contract, according to data from the INE website.
Five monthly contracts traded Monday for delivery in September, October, November, December 2018 and January 2019.
In addition, five quarterly contracts traded for delivery in the quarters ended March, June, September, December 2019 and June 2020.
