The Trump administration had wanted Iranian oil exports cut to zero by November 4.
The spokesperson then pointed to the global anger at the USA and Washington's policies towards its age-old allies, saying, "There is indication even in the Persian Gulf littoral states that there are concerns about Trump's policies, because they have the feeling that Trump is only seeking to empty their pockets".
On Wednesday, U.S. officials told reporters the naval fleet of Iran's Islamic Revolutionary Guard Corps (IRGC) is planning to use 100 gunboats in the Persian Gulf to practice "swarm" tactics, an exercise that is usually reserved for the fall.
U.S. officials are now travelling the world in a dramatic effort to stop other countries from buying Iranian oil. The financial news provider quoted informed officials on Friday as saying that the USA had been unable to persuade China to cut Iranian oil imports and that Beijing's purchases from Tehran last month remained unchanged.
Last month, Iran's Supreme Leader Ayatollah Ali Khamenei backed President Hassan Rouhani's suggestion that Iran may block Gulf oil exports if its own exports are stopped.
Sporadic protests broke out in several cities in Iran for a fifth night on Saturday, a day after demonstrators attacked a seminary, according to Iranian news agencies and social media, as Iranians brace for a return of United States sanctions.
China is Iran's top oil importer.
Francis Fannon, the assistant secretary of state for the Bureau of Energy Resources, was recently in China to discuss sanctions, according to a State Department spokesperson.
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.
The surge in imports has been attributed to perks offered by Iran before U.S. sanctions on the petroleum sector are enforced from 4 November, following the US's withdrawal from the 2015 nuclear deal.
Sanctions will also be reapplied to USA imports of Iranian carpets and foodstuffs and on certain related financial transactions.
Last month around 35 percent of Iranian oil exports went to China.
Chinese Foreign Minister Wang Yi said his nation will work to save the Iranian nuclear deal to ensure Iranian oil will continue to flow through the market, during a meeting with his Iranian counterpart Zarif.