Britain, France and Germany along with Russian Federation and China met with Iran in Vienna to offer economic benefits and assurances that would lessen the blow of sweeping U.S. sanctions announced by Trump.
Washington has since told allies they must stop buying the OPEC producer's oil from November 4 or face financial consequences.
While the other signatories have vowed to stay in the accord, dozens of European, Russian, and Asian companies have announced plans to pull out of Iran for fear of incurring US penalties when sanctions are reimposed in November.
A senior USA military leader said in 2012 the Guards have the ability to block the Strait of Hormuz "for a period of time" but the United States would take action to reopen it in such an event.
However, Rouhani told French President Emmanuel Macron by telephone on Thursday that the package of economic measures failed to offset sufficiently the effects of the US pullout and its re-imposition of nuclear-related sanctions.
"Unfortunately, the proposed package lacked an action plan or a clear road map for continuation of cooperation". Maas said more negotiations would be needed on the issue beyond Friday's meeting in Vienna.
As an original signatory to the deal, the USA - under then-President Barack Obama - also pledged to waive secondary American sanctions as long as Iran continues to abide by the agreement.More news: Asian markets tumble as China-US trade tensions rise
Iran is continuing to export oil despite U.S. attempts to prevent them from doing so, and there is no reason to think they're suddenly going to commit a series of acts of war in the Strait of Hormuz just to give the USA a pretext to attack them.
Mogherini said all participants had agreed to reconvene the JCPOA again at a later date.
A top United States official says on Jul 2 that Washington is determined to force Iran to change behaviour by cutting its oil exports to zero, confident the world has enough spare oil capacity to cope.
Iran's President Hassan Rouhani had Thursday told French President Emmanuel Macron by phone that the European offer of economic measures did "not meet all our demands", Iran's state news agency IRNA reported.
European Union High Representative for Foreign Affairs Federica Mogherini (L); Iranian Minister of Foreign Affairs Mohammad Javad Zarif (C) and political deputy at the Ministry of Foreign Affairs of Iran Abbas Araghchi take part in a Comprehensive Plan of Action (JCPOA) ministerial meeting on the Iran nuclear deal on July 6, 2018 in Vienna, Austria.
"If the process of the European foreign ministers' meeting in Vienna, which is aimed at encouraging Iran to cooperate, is promising, we will continue our cooperation", he said. "To save the deal, other signatories should compensate for USA sanctions", a senior Iranian official told Reuters on Friday.
Even though Iran's Foreign Minister Mohammad Javad Zarif said that the United States actions "de-facto disrupted the agreement", thus giving Iran a right to withdraw from it as well, the Islamic Republic would not exercise this right, according to Lavrov.