GENEVA (Reuters) - Yemen’s warring parties started on Friday a new meeting on a United Nations-backed prisoner exchange deal, which U.N. Yemen envoy Martin Griffiths said he hoped would result in the swift release of detainees. “The Yemen Prisoners & Detainees Committee meeting started today,” Griffiths said on Twitter. “I am grateful to Switzerland for hosting it, to the International Committee of the Red Cross for co-chairing.” “My message to the parties is conclude discussions, release detainees swiftly, bring relief to thousands of Yemeni families,” he added. The meeting is the fourth held by Yemen’s Houthi movement and the Saudi-backed government who had agreed to release conflict-related prisoners and detainees at talks held late in 2018 in Stockholm. Yemen has been mired in conflict since a Saudi-led coalition intervened in March 2015 to restore the Yemeni government ousted from power in the capital Sanaa by Houthi forces in late 2014.