The European Union's foreign policy chief Josep Borrell said Friday that a pause is needed in talks on reviving the 2015 Iran nuclear deal, formally known as the Joint Comprehensive Plan of Action (JCPOA), citing "external factors."

"I will, with my team, continue to be in touch with all JCPOA participants and the U.S. to overcome the current situation and to close the agreement," he tweeted, while noting that a final text of an agreement is "essentially ready and on the table."

Borrell did not give further details on when the negotiations will be reconvened.

Enrique Mora, the European Union (EU) coordinator in the Vienna talks, said after Borrell's announcement that the negotiators are "almost there" on reaching a deal and "have a text in which almost everything is done."

Mora said both Iran and the United States had taken a very constructive and positive approach in the negotiations.

"In order to keep this good spirit and atmosphere, it's better to pause," he said, adding that he hopes the talks could resume "very soon."

The sudden suspension of the Vienna talks came as participants of the negotiations revealed in recent days they were closing in on an agreement despite a few outstanding issues.

Mora on Monday called on the participants to make a political decision "in the next few days" to end the negotiations.

U.S. State Department Spokesman Ned Price said on Thursday that America was "close to a possible deal" that could even be reached "in the coming days."

Price added that "it's really down to a very small number of outstanding issues," but they are "among the most difficult ones."

However, Secretary of Iran's Supreme National Security Council Ali Shamkhani on Thursday slammed the U.S. approach to the Vienna talks, claiming that the absence of a political decision by the United States has complicated the negotiations.

"The U.S. approach to Iran's principled demands, coupled with its unreasonable offers and unjustified pressure to hastily reach an agreement, show that the U.S. isn't interested in a strong deal that would satisfy both parties," the Iranian official said on Twitter.

In 2015, Iran signed the JCPOA with the P5+1 (the five permanent members of the United Nations Security Council: China, France, Russia, Britain and the United States, plus Germany) and the EU.

However, former U.S. President Donald Trump unilaterally pulled Washington out of the pact in May 2018 and re-imposed sanctions on Iran. This prompted Iran to drop some of its nuclear commitments and advance its previously halted nuclear programs.

Since April 2021, Iran and the remaining JCPOA parties have held eight rounds of marathon talks in Vienna to restore the deal.