GENEVA - Yemen's Houthi group said on Friday it was still waiting for the United Nations to guarantee that the flight carrying its delegation to peace talks in Geneva would not be inspected by Saudi coalition forces and could evacuate some of its wounded.U.N.-brokered talks to end Yemen's three-year war were meant to begin on Sept. 6, but only representatives of the Yemeni government of Abd-Rabbu Mansour Hadi turned up as the Houthis insisted their plane to Geneva be allowed to evacuate dozens of injured people to neighboring Oman."The United Nations is now facing a choice where it should prove that it refuses the violation of the international and humanitarian law .... not allowing the Omani plane to take the delegation and the wounded is a flagrant violation," a Houthi leader, Mohamed Ali al-Houthi, said late on Friday on Twitter.Houthi said his group also wanted guarantees that their plane supplied by Oman would not have to stop in Djibouti for inspection in both directions, after being "sequestrated" there by the Saudi-led military coalition last time for months.The Saudi-led coalition intervened in Yemen's war against the Houthis in 2015 with the aim of restoring Hadi's government. Subsequent peace talks flopped. Since then, the humanitarian situation has worsened sharply, putting 8.4 million people on the brink of starvation and ruining the already weak economy.The United Nations wants the Yemeni government and the Houthis to work towards a peace deal, remove foreign forces from Yemen and establish a national unity government.Martin Griffiths, the United Nations Special Envoy for Yemen who set up the talks - the first in three years - has met the last two days only with the Yemen government delegation in Geneva, diplomats and U.N. officials said.His discussions with Yemeni Foreign Minister Khaled al-Yamani included humanitarian access, the reopening of Sanaa airport and the issue of prisoners, a U.N. spokeswoman told a briefing on Friday.Griffiths was working hard to get the Houthi delegation to Geneva, but the main stumbling blocks were its itinerary to the Swiss city and demands for evacuating war-wounded from Sanaa, diplomats and U.N. sources said.Later, a U.N. statement said Griffiths would give a news conference in Geneva on Saturday at 0800 GMT but gave no clue as to whether he would be in position to announce a break-through.The Yemeni government delegation is under pressure from allied Arab countries and the United States to stay in Geneva."The fact that if the (Houthi) delegation is not here, that doesn't mean that this has been a failure, it doesn't mean that we stop doing what we're doing," Matthew Tueller, US ambassador to Yemen, now based in Saudi Arabia, told reporters in Geneva on Friday."If they don't come we'll all be disappointed. But as I said I think the presence of the government delegation here has enabled all of us to make some progress on some of the issues of release of prisoners, perhaps even some of the ways that would allow for greater access of travel."Tueller, pressed on the issue of travel, said: "One of the issues that was to have been discussed here, and that there was a lot of preparatory work (on), would actually have enabled regular flights to evacuate wounded for treatment abroad."And so it's disappointing that the delegation from Sanaa isn't here or hasn't been able to be here to actually produce the results that we wanted to see," he added.The United Arab Emirates, a main member of the Saudi-led coalition, accused the Houthis of hindering the peace efforts."This condition ... can only interpreted as aiming to obstruct the talks," UAE Minister of State for Foreign Affairs Anwar Gargash tweeted on Friday.