The U.S. State Department said early Friday that Iran’s response to a U.S. proposal via the European Union to bring back the Iran Nuclear Deal was "not constructive." 

"We can confirm that we have received Iran's response through the EU. We are studying it and will respond through the EU, but unfortunately, it is not constructive," a spokesperson said. 

White House National Security Council spokesperson Adrienne Watson added: "Some gaps have closed in recent weeks but others remain."

Earlier, Iran’s foreign ministry said: "The text that was sent (by Iran) has a constructive approach aimed at finalizing the negotiations." 

IRAN, SYRIA CONSIDER FORMING JOINT OIL AND GAS COMPANY, STATE MEDIA SAYS 

Iran's president speaking

In this photo released by the official website of the office of the Iranian Presidency, President Ebrahim Raisi speaks during a press conference in Tehran, Iran, Monday, Aug. 29, 2022. (Iranian Presidency Office via AP)

The tense exchange comes after 16 months of negotiations to revive the multinational, Obama-era deal unilaterally abandoned by then-President Donald Trump in 2018. 

The EU has served as an intermediary for the indirect talks.

A Tehran nuclear facility

An engineer performs a mechanical test on nuclear equipment as President of Iran, Hassan Rouhani attends opening ceremony of nuclear projects in different regions of the country via video conference on 11th anniversary of National Nuclear Technology Day in Tehran, Iran on April 10, 2021.  (Iranian Presidency/Handout/Anadolu Agency via Getty Images)

OVER 5K FORMER SENIOR ISRAELI OFFICERS WRITE LETTER TO BIDEN URGING HIM NOT TO SIGN NEW IRAN NUCLEAR DEAL 

Under the deal, Iran curtailed its uranium enrichment in exchange for the lifting of some sanctions and was regularly inspected by the International Atomic Energy Agency. 

IAEA building

A picture taken on June 8, 2018, shows the logo of the International Atomic Energy Agency (IAEA) on the building of the IAEA laboratories in Seibersdorf, near Vienna.  (ALEX HALADA/AFP via Getty Images)

The country could only have 300 kilograms of uranium enriched up to 3.67% under the deal but, according to the latest IAEA count, now has around 3,800 kilograms enriched up to 60% purity.

Experts warn Iran has enough 60%-enriched uranium to reprocess into fuel for at least one nuclear bomb.

Iran denies it wants to build a nuclear bomb. 

CLICK HERE TO GET THE FOX NEWS APP

Earlier this week, Iran’s foreign minister said it needed a stronger commitment from the U.S. for the revival of the deal and for the IAEA to stop its "politically-motivated" inspections. 

The Associated Press and Reuters contributed to this report.