A suicide bomber killed at least 45 Yemeni soldiers after blowing himself up inside an army base in the southern city of Aden.
Yemeni officials said the bomber detonated himself as hundreds of soldiers collected their salaries in the Solban army base.
Over 40 soldiers have been wounded, reported AP. Reuters reported the death toll was at least 40, with at least 70 injured.
There was no immediate claim of responsibility for the attack.
AP reporters said the attack "bore the hallmarks of al-Qaeda" however Islamic State (Isis) also have a presence in the port city.
US government intelligence reports published by WikiLeaks showed that both terror organisations are funded by the governments of Qatar and Saudi Arabia.
A US State Department memo from 2014, while Hillary Clinton was secretary of state, said: "We need to use our diplomatic and more traditional intelligence assets to bring pressure on the governments of Qatar and Saudi Arabia, which are providing clandestine financial and logistic support to Isis and other radical groups in the region."
Saudi Arabia is currently engaged in conducting in a bombing campaign in the country after Houthi factions from the north rose up and deposed President Abdrabbuh Mansur Hadi from the capital of Sana'a.
Hadi resigned and fled to his hometown of Aden, but since receiving military assistance from Saudi Arabia, forces loyal to him have helped him reclaim the city from the Iran-backed Houthis.
The fighting has since raged on and the already poor country, considered to be the poorest of the Arab world, has been plunged into a humanitarian disaster.
More than 10,000 have been killed since 2014 and Oxfam estimates over 20 million people need assistance with basic necessities such as food and water – roughly half the country.
British Foreign Secretary Boris Johnson recently criticised Saudi Arabia's role in Yemen, accusing it of "puppeteering" and engaging in a proxy war to further its own political interests.
However, he has in turn been criticised for continuing Britain's arms sales to Saudi Arabia amid the bombing campaign.