A suicide car bomb attack on an army training camp in north Aden, Yemen's second major city killed at least 54 people on Monday, a security official said.
The director general of Yemen's health ministry in Aden, al-Khader Laswar, said at least 67 other people were wounded in the attack in the city's Mansoura district.
DAESH have claimed responsibility for the attack.
"Security services are still evacuating the dead and wounded" from the site, the official said.
The death toll may still rise.
The building was used by the Saudi-backed Popular Resistance, a local force that had helped drive Iran-allied Houthis out of the city last year.
At least 15 bodies were transferred to a hospital run by the aid group Medicins Sans Frontieres, a source at the hospital said.
The port city, the temporary base of Yemen's Saudi-backed government, has seen a wave of bombings and shootings targeting officials and security forces.
Yemen has been ravaged by civil war since late 2014, when Houthi rebels overran the capital Sanaa and a number of other provinces, forcing President Abd Rabbuh Mansur Hadi and his Saudi-backed government to temporarily flee to Riyadh.
In March of last year, Saudi Arabia and its allies launched a major military campaign in Yemen with the aim of reversing Houthi military gains and restoring Hadi’s embattled government.
Backed by Saudi-led air strikes, pro-Hadi forces have since managed to reclaim large areas of the country’s south — including the provisional capital Aden — but have failed to retake Sanaa and other strategic areas.
Attacks in Aden are often claimed by either Al Qaeda or DAESH, both of whom have taken advantage of the chaos in Yemen to make gains in the southern and southeastern regions.
More than 6,600 people, mostly civilians, have been killed in Yemen since March 2015 and more than 80 percent of the population has been left in need of humanitarian aid, according to the UN.