The Office of the United Nations High Commissioner for Human Rights is calling for the fighting to stop in northern Yemen’s Marib governorate, warning escalation of hostilities there is endangering the lives of hundreds of thousands of people.     The Marib governorate has been relatively unaffected by Yemen’s six-year long civil war.That is until Houthi rebels recently mounted a military offensive to try to seize control of the region from Yemeni government forces.   Because of its relative safety, hundreds of thousands of people have fled there to escape fighting in other parts of Yemen. At least 800,000 of them are now in the region.   U.N. human rights spokeswoman Liz Throssel says these and thousands of other civilians are in great danger.  She warns it is likely hundreds of thousands of civilians will be forced to flee the area if the front lines continue to move toward heavily populated parts of the governorate.   “Given the potentially disastrous humanitarian consequences, we call on all parties to the conflict to deescalate the situation and remind them of their obligations under international law to protect civilians from the adverse effects of the armed conflict.  This includes ensuring freedom of movement for the safe passage of civilians, including IDPs and migrants who are trying to leave Marib,” Throssel said.     Despite the war, Yemen attracts impoverished migrants from East Africa trying to reach Saudi Arabia in search of work. Throssel said thousands of these migrants are stranded under precarious conditions in Marib. “We are also concerned about the situation of 501 detainees in Marib’s Central Prison as the Yemeni authorities have indicated they have no contingency plan for them.  We are in the process of verifying information about recent civilian casualties in Marib, where over the last week Ansar Allah forces launched an offensive on several fronts,” Throssel said.      The Houthi movement is officially called Ansar Allah.  The U.N. human rights office, which monitors civilian casualties, reports 8,063 civilians have been killed and 12,046 injured since the war began in 2015.