Remaining parties to the 2015 nuclear deal, known as the Joint Comprehensive Plan of Action (JCPOA), namely Iran, the UK, China, France, Russia and Germany still have disagreements, but as a result of consultations, these points of differences have become clearer, Abbas Araqchi, also Iranian deputy foreign minister, was quoted as saying.

At the latest round of talks in Vienna, which started on April 27, negotiations were held at various levels and formats, and "they were very intensive", Araqchi said.

On May 1, "we decided to pause (the talks) to summarize the discussions", he added.

In some areas, "we have started writing the text, which is done very slowly", as the work requires precision, he said, adding the trend is moving forward.

Based on the JCPOA, Iran agreed in 2015 to roll back parts of its nuclear program in exchange for decreased economic sanctions.

However, Iran has gradually stopped implementing parts of its JCPOA commitments since May 2019, one year after the former US President Donald Trump's administration unilaterally withdrew from the agreement and re-imposed sanctions on the Islamic Republic.