A suicide bomber blew himself up inside an army base in the southern city of Aden on Saturday, killing 45 soldiers and wounding another 50, security officials said.
A bomber detonated a belt of explosives he was wearing amid hundreds of soldiers lining up to collect their salaries in the city's Solban army base, officials said.
Waleed Rashed, a soldier in the base, arrived at the scene shortly after the attack to find the area littered with bodies and blood.
"I could hear the wounded soldiers screaming for help," he said.
Private cars were used to ferry the wounded to hospitals before ambulances arrived, he added.
There was no immediate claim of responsibility for the attack but authorities suspect al-Qaida, which has carried out a series of deadly attacks in Aden over the years,
targeting government troops and senior security commanders.
The terror network's branch in Yemen is thought to be the world's most active. It is known to have a presence in Aden, where a loose coalition of troops loyal to the internationally recognized government of President Abed Rabbo Mansour Hadi, local militias and jihadi groups control the city.
The troops and jihadi groups are fighting Shiite rebels, who in 2014 seized Yemen's capital, Sanaa, and later swept much of northern Yemen. Their advances forced Hadi to flee the country and seek shelter in neighboring Saudi Arabia.
A Saudi-led coalition, mostly consisting of Gulf Arab states, subsequently intervened in Yemen, launching a punishing air campaign against the rebels and their allies.
(With AP inputs)