(190105) -- SANAA, Jan. 5, 2019 (Xinhua) -- A sick boy sits on an ambulance as he waits for the arrival of UN Special Envoy for Yemen Martin Griffiths at the international airport of Sanaa, Yemen, on Jan. 5, 2019. Martin Griffiths arrived in the rebel-held capital Sanaa on Saturday, in an apparent bid to cement the fragile cease-fire in Yemen's port city of Hodeidah. It was Griffiths' second visit to Sanaa in a month as the UN has been pushing for peace process in Yemen to end nearly four years of devastating war, which has pushed the Arab nation of more than 20 million people to the brink of famine. (Xinhua/Mohammed Mohammed)