MGN SANAA, Yemen (AP) – Al-Qaida militants in Yemen are pulling out of two coastal cities east of the key southern port of Aden following tribal-led negotiations, security officials and witnesses said on Thursday. The pullout from Zinjibar and Jaar is which is expected to take less than a week, they said. The officials spoke on condition of anonymity because they were not authorized to talk to reporters while the witnesses did so out of safety concerns. The development comes after forces loyal to Yemen’s internationally recognized government last month drove out al-Qaida militants from what had been their stronghold further down the coast, the city of Mukalla, a year after they captured it. Al-Qaida had gained ground amid the chaos that has reigned in Yemen since 2014 with Yemen’s Shiite Houthi rebels fighting the internationally-backed government and its allies with the Saudi-led coalition. The U.N. envoy for Yemen, Ismail Ould Cheikh Ahmed, expressed concern on Thursday over what he said were numerous violations of a truce between the warring sides. The envoy urged them to note that the violations impede fragile U.N.-brokered peace talks underway in Kuwait, according to the official Kuwait News Agency. Meanwhile, Aden’s civilian airport reopened on Thursday after months of closure due to security concerns, said Tarek Abdu Ali, the chief of the airport. The first passenger plane, coming from Jordan, landed around midday, he said Aden was one of the first cities retaken from the Houthis by government forces, with the help of the Saudi-led coalition last summer. But it fell into a state of lawlessness where Yemen’s al-Qaida branch and an Islamic State affiliate turned large parts of the strategic city into their militant strongholds. Earlier this year, the Saudi-led coalition led a series of security raids with help of air cover targeting the Islamic extremists.