Washington made a decision to reimpose sanctions on Iran upon its withdrawal, accusing it of posing a security threat, and has told countries they must halt all imports of Iranian oil from November 4 or face USA financial measures.
Chinese oil buyers had already slowed their purchases of USA oil to avoid a likely import tariff threatened by Beijing amid the trade dispute between the world's two largest economies.
But as the new Indian fiscal year began in April, refiners have been taking more Iranian oil imports compared to the previous fiscal year, as Iran offered incentives such as extended credit periods and nearly free shipping to keep its market share in India-Tehran's second-largest oil customer after China.
More than half-a-dozen current and former officials told the Reuters news agency that the campaign is meant to work in concert with US President Donald Trump's push to economically throttle Iran by re-imposing tough sanctions.
Francis Fannon, U.S. assistant secretary of state for the Bureau of Energy Resources, was recently in China to discuss sanctions, Bloomberg said, citing a U.S. government official.
The three European signatories to the nuclear deal, the United Kingdom, France and Germany agreed with China and Russian Federation last month to continue to support Iran through the reimposition of U.S. sanctions. "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.
Iran wants guarantees from Europe to maintain banking cooperation and investments in Iran's oil fields as well as continuation of cooperation between Iranian and European small and medium-sized enterprises, Qasemi noted.
The U.S., which withdrew from the nuclear deal in May, will re-impose some sanctions on Iran starting Monday.
Last month, United States officials familiar with the matter said the Trump administration had launched a communications campaign to foment unrest and put pressure on Iran to end its nuclear programme and its support of armed groups.
To keep its shipment flowing Iran has offered insurance for oil cargo and ships to supply oil to India, its top oil client after China.
The German finance ministry said this week, after Germany's Bild daily reported on the new Bundesbank rules, that the Iranian request is still under consideration - a process that involves Germany's financial market regulator and financial intelligence unit.