WASHINGTON — Talks resumed full-swing between Iran and the P5+1 member states Thursday, but amid increased rhetoric from each side blaming the other for intransigence, the US complained that Iran had still not demonstrated sufficient willingness to take the necessary steps to satisfy international concerns regarding its nuclear program.

“We are just asking for Iran to take concrete and verifiable steps to show that what they’re saying is true,” said a senior administration official Thursday afternoon. Although Iran has repeatedly said that its nuclear program exists only for civilian use, US officials complained that Iran will not agree to the steps that would ensure that the nuclear program could not be used to manufacture munitions.

Talks between Teheran and the P5+1 member states toward a comprehensive nuclear agreement in exchange for the lifting of sanctions against Iran have been held sporadically since the initiation of the Joint Plan of Action (JPA) in January. The JPA set a July 20 deadline for a comprehensive agreement to be reached, with the possibility of a six-month extension.

The senior administration official said that Iranian negotiators have repeatedly told their American counterparts that they hope to reach a deal by the July deadline.

But time, according to the official, is running out. The administrator said that many believed that Iran will wait until the last moment to begin to make concessions — and they emphasized that, with 17 days before the deadline, the last moment has arrived.

“This is not a mediation, a negotiation between two parties meeting each other half-way,” the official said. “This is about Iran meeting its obligations to the international community.”

US negotiators are expected to remain in Vienna and hold constant talks with their Iranian counterparts between now and the July 20 deadline. Previous rounds of talks have been held with significant breaks between rounds, but US officials conveyed the sense Thursday that they see this as the final stretch that will determine whether the sides emerge with a deal.

On Thursday, the US and Iran held a bilateral meeting, and both participated in a negotiations plenary session attended by the political directors of the negotiations. The US delegation also held a bilateral meeting with China, and a number of what officials described as “coordination meetings” were held both on Wednesday and on Thursday. Over the weekend, the parties’ experts who deal with the technical aspects of the negotiations are expected to meet.

Unlike the last round of talks held two weeks ago, in this round, the US delegation did not discuss the volatile situation in Iraq with their Iranian counterparts. The US and Iran have
not ruled out the possibility of increased coordination with each other regarding the advances made against Baghdad by Islamic State of Iraq and Levant (ISIL) forces.

The senior administration official complained that while Iranian Foreign Minister Mohammad Javad Zarif had accused the Americans of taking “maximalist” positions in the talks, in fact, they said, the US had shown flexibility and presented a number of “pathways” by which Iran could satisfy its international obligations.