Yemen’s warring sides on Sunday finalised a plan to implement the prisoner swap agreed to during talks in Sweden more than a year ago, the UN and Red Cross said. The UN Special Envoy for Yemen, Martin Griffiths, announced the breakthrough on Twitter after the parties held a third round of negotiations on the exchange in the Jordanian capital Amman. Mr Griffiths described it as "a step towards fulfilling their commitment to the phased release of all detainees related to the conflict in Yemen" under the Stockholm Agreement. It would be the “first official, large-scale” exchange of its kind since the start of the conflict in 2014, according to a joint statement by Mr Griffiths' office and the International Committee of the Red Cross. The prisoner swap agreement was seen as a major breakthrough during UN-brokered peace talks in Sweden in December 2018. The Iran-backed Houthi rebels and the internationally recognised government went on to agree to several confidence-building measures, including a ceasefire in the port city of Hodeidah. Implementation of the tentative peace plan stumbled amid Houthi breaches of the ceasefire and a deep distrust between the sides. The UN mission said the rebels and Yemeni government, which is supported by a Saudi-led military coalition, decided to “immediately begin with exchanging the lists for the coming release” of prisoners. Sunday's statement came after seven days of meetings in Amman. “Today the parties showed us that even with the growing challenges on the ground, the confidence they have been building can still yield positive results,” Mr Griffiths said. The UN mission did not disclose numbers for the expected prisoner exchange. Abdul Qader Al Murtaza, a rebel official in charge of prisoners’ affairs, said in a tweet that the first phase of the deal included the release of more than 1,400 prisoners from the two sides. Mr Al Murtaza said talks would continue for another two days to “prepare and revise the final lists”. The talks were co-chaired by Mr Griffiths’ office and the Red Cross. Representatives from the Saudi-led coalition also attended, the UN said. Mr Griffiths urged both parties to proceed with the prisoner exchange “with the utmost sense of urgency.” He did not say when they would start. Franz Rauchenstein, head of the Red Cross in Yemen’s capital, Sanaa, welcomed the step as “encouraging”. “Today, despite ongoing clashes, we saw that the parties have found common humanitarian ground that will allow many detainees to return to their loved ones,” Mr Rauchenstein said. Houthi spokesman Mohammed Abdel Salam said Saudi and Sudanese prisoners would be included in the release from his side. Sudan is a part of the Saudi-led coalition. Yemeni Foreign Minister Mohammed Al Hadrami said in a tweet on Sunday that he welcomed the “phased agreement” to release prisoners. The breakthrough came after another bout of intense fighting in different areas in Yemen, which killed and wounded hundreds . The conflict in the Arab world’s poorest country erupted in 2014, when the Houthis seized the capital and much of the country’s north. The Saudi-led coalition intervened in March the following year at the request of Yemeni President Abdrabu Mansur Hadi's government.