Saudi-backed forces loyal to Yemen's exiled government announced Monday the recapture of Abyan province in a southern offensive that has seen key gains against Shiite Huthi rebels.
Military officials who back President Abedrabbo Mansour Hadi told AFP that loyalist forces have retaken Loder, the last town in Abyan to fall from Huthi hands.
"Abyan is now completely free" of the Iran-backed Shiite insurgents, one official said.
There was no immediate confirmation from rebel sources that Loder had fallen.
The latest loyalist gain came as seven pro-government activists were handed over in Yemen's second city Aden as part of a prisoner swap overseen by the International Committee of the Red Cross (ICRC).
Loyalists had already taken Abyan provincial capital Zinjibar from the rebels and their allies on Sunday as they pressed an advance from second city Aden.
A medical source in Aden told AFP that 16 loyalist militiamen were killed and dozens wounded in Abyan over the past 24 hours, most when mines planted by retreating rebels exploded.
Local government officials said the deputy speaker of parliament and a former interior minister were wounded on Monday in Abyan province.
Mohammed al-Shaddadi and ex-minister Hussein bin Arab, who are close to Hadi, were leading loyalist forces in Loder at the time, they said without elaborating.
Like Hadi, both men are from Abyan.
Loyalists forces secured Aden in mid-July and Lahj provincial capital Huta on August 4 before advancing on Abyan, backed by a Saudi-led Arab coalition waging an air war against the rebels since March.
- Aden prisoner swap -
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Clashes were also reported by residents in third city Taez on Monday, as well as in the central province of Ibb.
However, the rebels still control the capital Sanaa which they seized last year, as well as large swathes of Yemen including the remote north where their mountain stronghold of Saada is located.
Monday's prisoner swap overseen by the ICRC involved activists of the Southern Movement, a secessionist group which helped to push the rebels out of Aden last month.
Rebel officials said the seven were released in exchange for the same number of Huthi militiamen.
A security official at Aden airport said the activists were handed over to the loyalist so-called Popular Resistance Committees.
The activists departed with ICRC head Peter Maurer aboard a Red Cross plane, according to an AFP photographer who saw the prisoners at the airport.
Maurer arrived in Sanaa on Saturday for a three-day visit to assess the "dire humanitarian situation" in Yemen.
In Aden, he visited the wounded in hospitals and met top medical officials, said the city's health chief Al-Khader Laswar.
Maurer wrapped up his visit and flew out to Djibouti, security officials at Aden airport said, adding that he did not oversee the release of the seven Huthi prisoners.
AFP could not immediately confirm if the Huthis had been released.
The United Nations says nearly 4,000 people have been killed since March, half of them civilians, while 80 percent of Yemen's 21 million people need aid and protection.
The ICRC says 1.3 million Yemenis have been displaced by the conflict.