Four gunmen stormed the care home in Aden's Sheikh Othman district, killing a guard and shooting randomly at residents, the officials told AFP.
Dozens of stricken family members arrived at the site following the attack, witnesses said.
One official said the attackers were "extremists" and blamed Daesh (known as ISIL) for the attack.
But no group claimed responsibility for the attack.
In recent months, Saudi-backed al-Qaeda and ISIL terrorists have stepped up attacks in Aden as part of Riyadh’s plan to undermine Houthi revolutionary forces.
On March 26, Saudi Arabia and some of its Arab allies began to launch deadly airstrikes against the Houthi Ansarullah movement in an attempt to restore power to the fugitive former President Abd Rabbuh Mansour Hadi, a close ally of Riyadh.
The death toll from the Saudi-led war so far has reached more than 8000 people. More than half of the total population of Yemen, some 14.4 million people, are also food insecure due to ongoing conflict and import restrictions, according to the Food and Agriculture Organization (FAO).