U.S. officials are now travelling the world in a dramatic effort to stop other countries from buying Iranian oil.
Beijing, however, agreed not to increase purchases of Iranian crude, said the officials who spoke on condition of anonymity. "When we decide anything on Iran, we will inform you".
Iran's currency plummeted this week in the lead-up to 7 August, when Washington is due to reimpose a first lot of economic sanctions following Trump's withdrawal from the nuclear deal.
The surge in imports has been attributed to perks offered by Iran before United States sanctions on the petroleum sector are enforced from 4 November, following the US's withdrawal from the 2015 nuclear deal.
The oil market has been speculating about how much of Iran's exports could be eroded by the USA sanctions, with analysts from BMI Research to Mizuho Securities predicting that China might boost its imports of cheap supplies from the state and offset cuts by other nations.
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While the video doesn't show an explosion, the witness said it fell and then exploded, starting a fire in the building. He says the economic malaise gripping Venezuela is an "economic war" and any unrest is plotted by foreign powers.
"The Americans say they want to reduce Iranian oil exports to zero ... It shows they have not thought about its consequences", Rouhani was quoted as saying by state news agency IRNA while on an official visit to Austria's capital, Vienna, in July.
She told CNBC with regards to the USA sanctions against Iran kicking in next week, "we're looking at tougher rhetoric and potentially tougher actions over August and September".
Also last month, China, which is Iran's biggest customer, said it did not accept unilateral sanctions against Iran.
"China will continue to cooperate with Iran adhering to its worldwide obligations".
Tamar Essner, an analyst at Nasdaq Inc., said there are "no signs whatsoever that this trade war is going to clear up anytime soon", and that has "caused investors to continue to trim net length, take profits, and de-risk that position with the sense that oil's upside is limited unless there's material reduction in Iranian barrels".
Russian oil output rose by 150,000 barrels per day (bpd) in July from a month earlier to 11.21 million bpd, energy ministry data showed on Thursday. This accounted for 35 percent of Iranian exports last month, according to ship-tracking data compiled by Bloomberg.