The United Nations envoy to Yemen resigned on Wednesday after four years in the role, as fighting in the country continues to rage on.
Jamal Benomar, a Moroccan diplomat, had been a mediator between various political organisations since 2012 after he brokered a 2011 transition plan following the Arab Spring. Since then the situation in the country has deteriorated with a Saudi-led collation bombing campaign now entering its fourth week.
UN chief Ban Ki-Moon released a statement saying he "greatly appreciates the tireless efforts Mr. Benomar has made over the years to promote consensus and trust on a peaceful way forward in Yemen".
"A successor shall be named in due course. Until that time and beyond, the United Nations will continue to spare no efforts to re-launch the peace process in order to get the political transition back on track," the statement added.
Mauritanian diplomat Ismail Ould Cheikh Ahmed has been tipped to take up the post.
Mr Benomar had faced criticism during his time as UN envoy, with, a Gulf diplomatic official accusing him last month of appeasing Houthi militants as they seized large parts of the country.
"They pressed to redraw the political map of Yemen and, in a way, they were encouraged by Benomar," the official said.
However, Yemen's vice president, Khaled Bahah, told reporters in Riyadh, the capital of Saudi Arabia, that, "if something did not happen during the dialogue or there was a failure, Benomar should not be blamed for that - it's the political parties that did not help Benomar."