Dozens of Yemeni army recruits killed in twin blasts
The first blast saw 34 men killed as a bomber detonated his suicide belt after joining the queue at a recruitment centre near the Badr base in the Khormaksar district of Aden, security sources told The New Arab.
Another seven army recruits were killed by a second bomb attack inside the base, sources added.
Scores more were injured in the attacks, security officials said.
IS claimed responsibility for the blasts, which appear to be the latest in a series of similar attacks against government forces in Yemen.
Last week, dozens of police recruits and army officers were killed in multiple attacks on the southern city of Mukalla claimed by the militant group.
More than 13 months of conflict in Yemen has allowed armed groups such as IS and al-Qaeda to flourish across the country, with particular focus on the southern region - where several areas are under the control of Al-Qaeda in the Arabian Peninsula.
Attacks have been frequent, with dozens of police officers and military personnel targeted and killed by militants who accuse the government of "apostasy".
Saudi Arabia, the UAE and other Arab countries intervened in Yemen's civil war in March 2015 in support of the internationally recognised government, which had been forced into exile by the Iran-backed Houthi movement.
Last week, the United States said that "a very small number" of US soldiers were also involved in operations in Yemen.