Oil prices rose on Monday, supported by concerns that falling Iranian output will tighten markets once USA sanctions bite from November, but gains were limited by higher supply from OPEC and the United States.
International Brent crude futures LCOc1 , by contrast, lost ground, trading at $78.10 per barrel, down 5 cents from their last close.
US West Texas Intermediate (WTI) crude futures were at $69.31 per barrel at 0517 GMT, down 56 cents, or 0.8 percent, from their last settlement.
Oman'soil minister, also speaking to CNBC, said not enough attention was being paid to how trade tensions could damage China's demand for oil.
Jiji Press agency and Kyodo on September 3 reported that the action comes in response to USA sanctions against Tehran and threats they could be extended to companies doing business with Iran.
Though the sanctions are officially taking in November, Iran is already seeing customers flee as the US imposes penalties on buyers after President Donald Trump backed out of a 2015 nuclear accord with the country, Bloomberg reported.
"This is because of the USA dollar's strength, weighing heavily on emerging market currencies, including the yuan, which in turn has pushed up the costs of all dollar-denominated commodities", he said.
David Maher, managing director for energy at commodity trading house RCMA Group, said Venezuela's "declines will continue" as a "lack of cash and infrastructural collapse (are) not easy to fix".
OPEC crude production rose in August to the highest level this year as a recovery in Libyan output helped to offset a cut in Iranian exports due to USA sanctions. Crude is up 9% since mid-August as WTI flirts with $70 per barrel.
"Iranian production is already showing signs of decline, falling by 150,000bbl/day last month ..."
Barclays bank said on Tuesday oil markets had changed since 2017, when worries about rising supply were more evident.
In August, Russia produced 11.21 million barrels of oil per day according to data mailed by Russian energy ministry to Bloomberg.
Many analysts have warned that an economic slowdown because of trade disputes between the United States and other major economies including China and the European Union would drag on oil demand.
Oil prices fell on Wednesday as a tropical storm hit the US Gulf coast with high winds and heavy rain, but the impact on production was not as strong as initially expected.