Iran’s President Hassan Rouhani said on Monday Tehran would continue to scale back its commitments to the 2015 nuclear agreement until the European Union fulfils promises it made under the deal. Iran has gradually scaled back its nuclear commitments since May after the US pulled out of the deal and has called on European parties to the pact to salvage the deal by shielding Iran’s economy from US penalties. Rouhani, speaking on state television, also said Iran would start working on more advance uranium enrichment centrifuges. Meanwhile, a team of British experts arrived in Iran on Monday to begin work to upgrade the Arak heavy water nuclear reactor, the UK embassy in Tehran said. Iran removed the core of the Arak facility and filled part of it with cement as part of the 2015 deal. Located southwest of Tehran, the reactor is to be modernized with the help of foreign experts under the deal known as the Joint Comprehensive Plan of Action. "A team of British nuclear experts led by UK Chief Scientific Adviser Professor Robin Grimes arrived in Tehran today to take forward the next stages of the modernization of the Arak reactor, alongside a team of Chinese experts," said the British embassy. "The experts will hold talks with the Atomic Energy Organization of Iran on international technical assistance to the reactor construction," it said in a statement. The British experts would remain in Iran for three days, the embassy told AFP. Tensions have been escalating between Iran and the United States since May last year when President Donald Trump pulled out of the nuclear accord and began reimposing sanctions. The remaining partners in the deal with Iran include Britain, China, France, Germany and Russia. The European parties have repeatedly said they are committed to saving the accord, but their efforts have so far borne little fruit. Tehran has already hit back three times with countermeasures in response to the US withdrawal from the nuclear deal. On July 1, Iran said it had increased its stockpile of enriched uranium to beyond a 300-kilogram maximum set by the deal, and a week later, it announced it had exceeded a 3.67-percent cap on the purity of its uranium stocks. In its latest move it fired up advanced centrifuges to boost its enriched uranium stockpiles on September 7.