The European Union's top foreign policy official has called for a concerted effort to use what he has referred to as a "diplomatic window of opportunity" in order to revive a 2015 nuclear agreement signed between Iran and major world powers.

“This is an occasion that we cannot miss,” to reinvigorate the nuclear accord, officially known as the Joint Comprehensive Plan of Action (JCPOA), EU foreign policy chief Josep Borrell told reporters on Friday via video-link.

The future of the JCPOA has been in doubt since May 2018, when the US under ex-president Donald Trump pulled out of the agreement and imposed the “toughest ever” sanctions on Iran as part of his so-called “maximum pressure,” which tried in vain to force Iran back to the negotiating table for talks on a “better deal.”

Despite throwing verbal support behind the JCPOA, the European parties to the deal — France, Britain and Germany — ultimately succumbed to Washington’s pressure and failed to fulfill their contractual commitments to Tehran, mainly by confronting the American sanctions.

That promoted Tehran to begin a set of retaliatory measures in several stages as part of its legal rights stipulated in Articles 26 and 36 of the JCPOA. The latest such measure was the halt in the implementation of the Additional Protocol, which was required by the parliament-adopted law.

“I am convinced as coordinator of the JCPOA that we do have diplomatic space, a diplomatic window of opportunity to dialogue,” Borrell said.

The top EU diplomat added, “We need to use this opportunity and focus on solutions to bring the JCPOA back on track in order for everybody (to fulfill) their commitments.”

Joe Biden, the current president of the United States, has repeatedly spoken of a willingness to rejoin the Iran deal, but, in practice, it has so far been sticking with Trump’s futile pressure campaign. It says Tehran should return to full compliance with the deal before the US comes back.