A suicide bomber has killed at least 25 people and injured 54 others while targeting police recruits at a security compound in the southern Yemen city of Mukalla, security officials say.
The officials spoke on condition of anonymity on Sunday because they are not authorised to speak to the media.
Some of the victims were policemen returning to work following last month's recapture of Mukalla by forces of the internationally recognised government.
Other victims included young men applying for jobs with the city's local police.
The Islamic State of Iraq and the Levant (ISIL, also known as ISIS) group has claimed the attack, the second but rare intervention by the group in an area known as a stronghold of rival al-Qaeda.
On Thursday, 15 Yemeni troops were killed in attacks on army positions outside Mukalla. ISIL said one of its fighters blew up a vehicle packed with explosives in an army base in Khalf district on the city's eastern outskirts.
The port city has been held for more than a year by Yemen's local al-Qaeda affiliate, Al-Qaeda in the Arabian Peninsula (AQAP).
The US has stepped up a long-standing drone war against AQAP in recent weeks.
But armed groups retain a strong presence and still control several towns in the interior valley of Wadi Hadramawt.
The Yemen conflict has killed more than 6,400 people and displaced 2.8 million since March last year.