Under the 2015 pact, signed by the US, UK, Britain, China, Russia and the European Union, Tehran agreed to scale back its uranium enrichment programme.
The matter is awkward for Germany because the government is also committed to keeping alive the 2015 deal it, along with the United States and other world powers, signed with Iran which provides incentives in exchange for Tehran not pursuing a nuclear weapon.
Changes to its business conditions taking effect August 25, and released in late July, allow the Bundesbank to block cash transfers in the absence of assurances from those involved in a transaction that it doesn't violate financial sanctions or rules to prevent money-laundering and the funding of terrorism.
The US is due to impose a series of new sanctions on Iran in the next few months.
India's imports from Iran could start to slow from August as some big Indian refiners worry that their access to the USA financial system could be cut off if they continue to import Iranian oil, prompting them to reduce oil purchases from Tehran.
She added that while China may not cut Iranian oil imports, it did not indicate that it will increase imports either, raising the question of whether or not there will be 1 million barrels per day of Iranian oil take off the market by the end of this year and whether OPEC can make up for the shortfall.
If the US wants negotiations, it should stop pressures and sanctions, Qasemi was quoted as saying by official IRNA news agency.
"Iran will survive this round of United States sanctions as it has survived them before", Rouhani said, describing them as a "crime and aggression".
"The unilateral sanctions should be abandoned because they are counterproductive", Chinese Foreign Ministry spokesperson Hua Chunying told reporters. "China will continue to cooperate with Iran adhering to its global obligations", she added.
Another expert who foresees tightening was far more outspoken in his short-term forecast: Stephen Brennock, oil analyst at PVM Oil Associates, stated in a note on Friday that "Venezuela's ticking time bomb together with the return of Iran's oil industry to the sanctions era has all the makings for a major supply shock". This accounted for 35 percent of Iranian exports last month, according to ship-tracking data compiled by Bloomberg.