AL MUKALLA, Yemen — A suicide bomber disguised as a disabled man blew himself up at a gathering of Yemeni security officers in the southern port of Aden on Sunday, killing 48 people and wounding dozens of others, Yemeni officials said.

The Islamic State claimed responsibility for the attack, naming the attacker and publishing a photograph of him smiling with a rifle at his side and wearing an explosive vest.

The attack was the second this month to kill scores of security forces near a military base in Aden, highlighting the failure of the Yemeni government and its allies to ensure basic security in the areas they control.

Yemen has been mired in conflict since 2014, when rebels aligned with Iran, known as the Houthis, seized the capital, Sana. They later forced the internationally recognized government into exile in Saudi Arabia.