Media Advisor to the Yemeni Supreme Political Council, Ahmed al-Habishi, announced Monday that former Yemeni President Ali Abdullah Saleh has been killed in the area controlled by UAE air force.
The mediation effort came as supporters of the 2012-ousted president battled the Houthi militias in Sanaa, until finally Saleh announced that Yemen's parliament, dominated by his party, was the only legitimate power in the country.
Two of Mr Saleh's associates and a third official from the government of Yemen's internationally recognised president, Abed Rabbo Mansour Hadi, have confirmed the death.
Yemen is one of the Middle East's poorest countries, and the war has caused one of the worst humanitarian catastrophes of recent years.
Al Arabiya quoted a source in Saleh's GPC party as saying he was killed by a sniper.
The breakdown of the alliance has led the coalition to step up its bombing of Houthi positions, in support of Saleh's forces.
Inside the city, residents said that Houthi fighters seized television studios of Yemen Today, a news channel owned by Saleh, after clashes that damaged the building.More news: Disney's Live-Action 'Mulan' Casts Liu Yifei in Title Role
Residents reported that the fighting, which erupted Wednesday, had spread outside the capital.
Saudi Arabia, accusing arch-rival Iran of backing the rebels, intervened in the Yemen war on behalf of the government the following year.
The news that Saleh had been killed came just hours after Saudi Arabia chose to back Saleh, calling his fight against the Houthis a "popular uprising".
Saudi forces have been widely accused of committing war crimes during the campaign in the country, where reports on the ground suggest they have blown up global hospitals, funerals, schools, and weddings.
The coalition imposed a total blockade in October on the country, where almost 80% of the people need humanitarian aid to survive.
In response, Houthi chief Abdul-Malek al-Houthi made a surprise speech this morning, calling on Saleh and tribal leaders to intervene to stop the internal bloodshed and reunite the internal ranks to face the "aggression", in reference to the Saudi-led military coalition.
The ex-president also called for an end to the "militia's rule on Yemen's land", adding that the Houthis had continued their "provocative acts against Yemeni citizens". It gave no further details.