GENEVA (Reuters) - The United Nations has verified 5,144 civilian deaths in the war in Yemen, mainly from air strikes by a Saudi-led coalition, and an international investigation is urgently needed, U.N. human rights chief Zeid Ra ad al Hussein said on Monday.   The minimal efforts made toward accountability over the past year are insufficient to respond to the gravity of the continuing and daily violations involved in this conflict,  Zeid said in a speech to the U.N. Human Rights Council in Geneva.  The devastation of Yemen and the horrific suffering of its people will have immense and enduring repercussions across the region.   It is the third time that he has appealed for an international inquiry into human rights violations in Yemen where a two-year conflict pits the Saudi-backed Yemen government against Iran-supported Houthi rebels. Last week Zeid s office said the 47 countries on the Human Rights Council were not taking their responsibilities seriously, and urged them to probe the  entirely man-made catastrophe . The U.N. says the civil war has created the world s biggest humanitarian crisis, with the conflict compounded by an economic collapse that has pushed millions to the brink of famine. The crippling of the health and sanitation systems has enabled cholera to take hold with unprecedented speed, with about 650,000 people infected since late April, five times the global cholera caseload in 2016. During the three-week U.N. Human Rights Council session, Saudi Arabia and the Netherlands are expected to propose rival resolutions, inviting the council to continue backing Yemen s national human rights probe or to set up its own inquiry. For the past two years, Saudi Arabia has prevailed, but the situation in the country has not improved, and Zeid s office has said Yemen s national investigation is not up to the job. The draft Dutch resolution backs Zeid s position, a Western diplomat said.   The common assessment is that the situation has deteriorated. The compromise that was put in place last year hasn t delivered,  the diplomat said.  One of the resolutions will need to be dismissed.  