The Arab coalition announced on Sunday that it had carried out 19 air raids over the past day, killing 100 Houthi fighters and destroying 14 military vehicles in Marib province.

On the ground, heavy fighting between government troops and Houthis broke out on Saturday and Sunday outside the city of Marib, local official and media reports said.

The heaviest fighting was recorded in Juba district, south of Marib, where the Houthis intensified attacks in a bid to overwhelm the government’s defenses on a strategic mountain range that overlooks parts of the city.

The Houthis failed to register any territorial gains on Sunday and were forced to retreat after suffering heavy losses, officials said.

Thousands of combatants and civilians have been killed since February when the Houthis renewed an offensive to seize control of the energy-rich city, the government’s last bastion in the north.

Separately, Iran’s ambassador in the Houthi-held Yemeni capital, Sanaa, departed the city on Saturday onboard an Iraqi medical aircraft, the movement’s spokesperson and local media said.

Mohammed Abdul Salam said that a successful Iraqi mediation between Iran and Saudi Arabia led to the medical evacuation of Hassan Erlo through Sanaa airport, denying media reports about tensions between the movement and Iran and rumors that he was wounded in airstrikes by the Arab coalition.

“An Iranian-Saudi understanding through Baghdad led to the evacuation of the the Iranian ambassador to Sanaa on an Iraqi plane due to his health condition,” Salam said on Twitter.

In Tehran, the Iranian Foreign Ministry said that its ambassador was flown back home after contracting COVID-19 during his stay in the capital.

The Wall Street Journal reported on Friday that the Houthis sent a request to the Arab coalition to permit the evacuation of the Iranian ambassador, a move that was interpreted as suggesting a possible rift between the Yemeni rebels and Iran.

Hassan Erlo, an officer in Iran’s Islamic Revolutionary Guard Corps, traveled to Yemen in October last year and was later named as Iran’s ambassador to the Houthis.

Yemeni officials and experts believe that Erlo orchestrated the militia’s deadly offensive to capture the central city of Marib and also commanded other Iranian, Iraqi and Lebanese officers who provided the rebels with military guidance.