The United Nation's top humanitarian co-ordinator has said Yemen is facing total social, economic and institutional collapse. <br/><br/>Stephen O'Brien was speaking to the UN Security Council, telling them urgent action is required. Yemen is in the midst of a humanitarian crisis, with almost seven million people on the brink of famine. <br/><br/>An outbreak of cholera has also killed 500 people. Mr O'Brien said the suffering of Yemenis was not a coincidence, or the result of forces beyond our control but rather the fault of those involved and inaction by world powers.<br/><br/>Al-Qaeda, meanwhile, has taken advantage of the chaos to reinforce its presence in the south and south-east of the country. <br/><br/>UN figures say that more than 8,000 people – mostly civilians – have been killed and close to 44,500 others injured since the conflict escalated in March 2015. An estimated 18.8 million people are in need of humanitarian assistance.