(Middle East Eye) – The United Nations on Tuesday urged the Saudi-led coalition to end a blockade on Yemen’s air, sea and land borders that prevented it on Monday from sending two humanitarian aid flights to the war-torn country. It comes as Houthi rebels threatened retaliation against the ports and airports of the United Arab Emirates and Saudi Arabia and as Iran moved to dismiss accusations by Saudi Arabia that it was behind a missile fired by Houthi rebels what was intercepted above Riyadh.