Update as of 5:19 a.m. EDT: Jamal Benomar, the United Nations envoy to Yemen, stepped down from his position on Wednesday, Reuters reported, citing his official Facebook page. The departure of Benomar underlines the failure of U.N. efforts to end the fighting in Yemen, which has left hundreds of people dead since the conflict intensified in mid-March.

Original story:

The United Nations' special adviser to Yemen, Jamal Benomar, plans to resign to from his job amid the escalating armed conflict in the country, a report said Thursday, adding that U.N. Secretary General Ban Ki-moon is considering a Mauritanian diplomat to replace Benomar.

Saudi Arabia and other Persian Gulf countries were reportedly unhappy with Benomar’s handling of the unsuccessful negotiations between the Iran-linked Houthi rebels and the beleaguered Yemeni government. The Gulf countries also believe that Benomar, an experienced Moroccan diplomat, was partial to the Shiite Houthi militants, Reuters reported, citing Western U.N. diplomats. Sunni Saudi Arabia and its neighbors support the government of President Abed Rabbo Mansour Hadi while the Houthi rebels are believed to have the backing of Shia Iran.

“A successor shall be named in due course,” a spokesperson for the U.N. chief told Reuters. “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.”

According to Reuters, Mauritanian diplomat Ismail Ould Cheikh Ahmed is expected to take over the post, but it was not clear when the appointment would take place.

Yemen has been in a state of turmoil since Houthi rebels took control of the capital city of Sanaa in September. The rebel fighters also closed in on the port city of Aden, forcing Hadi to flee the country and seek refuge in Riyadh.

The Houthis and supporters of Yemen’s former President Ali Abdullah Saleh have banded together to fight army units loyal to Hadi, while a Saudi Arabia-led coalition has been conducting airstrikes against Houthi rebels in several parts of the country for the past three weeks in an effort to bring Hadi back to power.