Pro-government forces launched a major offensive on Monday, seeking to recapture the strategic al-Anad base, Yemen's largest air base.
The Saudi-led coalition provided more than 1,000 troops - the majority of them from the United Arab Emirates (UAE) - along with armored vehicles and tanks, reported Saudi-owned periodical Al-Hayat.
Around 60 kilometers (35 miles) north of Aden, the al-Anad air base served as a launching pad for US drone attacks against al-Qaeda in the Arabian Peninsula (AQAP) before being overrun by Houthi rebels in March.
Military officials said forces loyal to exiled President Adebrabbo Mansour Hadi had gained control of the air base's western gate.
However, Houthi officials said they were still in control of al-Anad air base, which has served as the rebel group's center for operations in southern Yemen.
Prime Minister Khaled Bahah returned to Aden on Saturday after pro-government forces recaptured the coastal city in July, marking a major setback for the Shiite rebels, who gained control of large swathes of land in Yemen in 2014.
According to the UN, more than 3,400 people have been killed - half of them civilians - since Saudi Arabia launched a military campaign against Houthi rebels in March in a bid to reinstate exiled President Hadi.
Around 13 million people are reported to be in dire need of food and basic amenities, with the International Committee of the Red Cross saying civilian suffering has reached "unprecedented levels."
ls/jil (AFP, AP, Reuters)