GENEVA - The UN envoy to Yemen believes his plan to end a four-month conflict that has triggered a humanitarian crisis in Yemen is increasingly gaining acceptance among the warring parties, a UN spokesman said on Tuesday.On a visit to Cairo, UN envoy Ismail Ould Cheikh Ahmed met the secretary-general of the General People's Congress (GPC) party, which supports former president Ali Abdullah Saleh, and Nabil Elaraby, the secretary-general of the Arab League, UN spokesman Ahmad Fawzi said."He feels his plan is gaining more and more acceptance among the parties. Riyadh has a indicated positive reaction towards the plan, the GPC is considering it positively," he said.The five days of talks in Geneva produced agreement in principle on a ceasefire and withdrawal of armed forces. The talks broke up before a final deal could be agreed, but Ould Cheikh Ahmed said he remained optimistic.Fawzi said that after Egypt, Ould Cheikh Ahmed would go to Oman, where he has previously met Houthi representatives, and to Riyadh, home to Hadi's government in exile, and then to New York to brief the UN Security Council.Fawzi denied that Ould Cheikh Ahmed had discussed the possibility of negotiating Saleh's exit from Yemen, but added that Arab League secretary-general Elaraby had told the envoy that the league would consider monitoring a ceasefire in Yemen. UN-led talks in June between northern Houthi rebel fighters and supporters of the government of President Abd-Rabbu Mansour Hadi failed to end the war, in which the United Nations says nearly 2,000 civilians have been killed.A stand-off between the two sides escalated in late March when a Saudi-led Arab coalition began a campaign of air strikes against the Houthis and their allies, loyalists of Saleh.