At least 20 government soldiers were kidnapped and executed in southern Yemen on Saturday, local officials and residents said.

The troops were seized while travelling from the southern port of Aden to al-Mahra province in eastern Yemen via Ahwar, a city in Abyan province that has been under al-Qaeda control.

Officials and residents said the captive soldiers, who were aligned with President Abd-Rabbu Mansour Hadi, were taken to a remote area and killed by firing squad.

Seventeen other soldiers were wounded in the incident, with some managing to escape and get help from local tribal leaders, they added.

A military source told the AFP news agency that the executions had been carried out by al-Qaeda fighters.

"Armed members of al-Qaeda ambushed a group of young soldiers travelling in three civilian vehicles in the province of Abyan, killing at least 20 of them," the source, who requested anonymity, said

Al-Qaeda denial

But Ansar al-Sharia, an al-Qaeda affiliate in Yemen, later issued a statement denying responsibility for the attack and blamed a local armed fighter named Ali Aqeel.

"We entered Ahwar around two months ago to chase this corrupt individual and his gang," the statement said.

Yemen has been at war since September 2014, when Iran-backed Houthi rebels and their allies drove the government out of the capital Sanaa and much of the country's north.

The Houthis controlled Aden, the main city in southern Yemen, for months before government forces backed by a Saudi-led Arab coalition pushed them back in July.

Al-Qaeda in the Arabian Peninsula (AQAP) has exploited the chaos to expand areas under its control and recruit more followers.

Ceasefire and peace talks

There have already been several failed attempts to defuse the conflict, which has killed about 9,000 people, including more than 3,000 civilians, over the last year, according to the United Nations.

Yemen is facing a humanitarian catastrophe, with millions of people without enough food or access to adequate medical care.

Under a UN-brokered agreement, a ceasefire between Yemen's warring parties is due to begin on Sunday ahead of peace talks scheduled for April 18 in Kuwait.

Hours before the start of the truce, a spokesman for the Arab coalition said the alliance is ready to commit to a ceasefire, as long as the Houthis abide by a UN Security Council resolution that calls for their pullout from Yemeni cities.

Brigadier General Ahmed al-Asiri told The Associated Press news agency that the Houthis should "show commitment" to the upcoming peace talks that could yield a political settlement.

The rebels must also recognise Hadi's government and hand over their heavy weapons, he added. If talks fail, al-Asiri said the military option remains on the table.

"The two tracks are parallel: the political and the military. Whatever way leads to the restoration of the internationally recognised government, we will take," al-Asiri said, speaking in the Egyptian capital, Cairo.