UNITED NATIONS, Nov 17 - A Saudi-led military coalition fighting Houthi rebels in Yemen is threatening the peace, security and stability of the country by blocking humanitarian aid, United Nations sanctions monitors told the Security Council in a confidential report.The independent monitors also called on the coalition to provide evidence backing Riyadh's claim that Iran was supplying missiles to the Houthi rebels, warning that a failure to do so would violate a February 2017 council resolution.The coalition said on Nov. 6 it had closed all air, land and sea ports in Yemen to stem the flow of arms to the Houthis from Iran, after Saudi Arabia intercepted a missile fired towards its capital Riyadh. It has since said that aid can go through "liberated ports" but not the key Houthi-controlled port of Hodeidah.The United Nations has appealed for the blockade to be lifted, saying it could spark the largest famine the world has seen in decades. Some seven million people are on the brink of famine and nearly 900,000 have been infected with cholera."Saudi Arabia-led coalition restrictions to the delivery of humanitarian assistance fall under resolution 2216 (2015) as an obstruction to the delivery of humanitarian assistance," the UN monitors wrote in the executive summary of their report, seen by Reuters on Friday.