At least 16 people, including four Indian nurses, were killed when gunmen opened fire Friday at an elderly care home in Yemen's main southern city of Aden, security officials said.
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 the Islamic State group, which has been gaining ground in Aden in recent months.
But no group claimed responsibility for the attack, the first of its kind in Yemen, where the internationally-recognised government is grappling with an Iran-backed rebellion on one side and a growing jihadist presence on the other.
President Abedrabbo Mansour Hadi has declared Aden Yemen's temporary capital as Sanaa remains in the hands of the Huthi rebels and their allies since they seized it in September 2014.
Al-Qaeda and IS have stepped up attacks in Aden despite the efforts of the government and its backers in a Saudi-led coalition battling the Huthis and their allies to secure it.
However, most of the jihadists' attacks have targeted coalition forces and pro-government Yemeni troops.
On Monday, a suicide car bombing, also in Sheikh Othman, hit a gathering of loyalist forces killing four people and wounding five others, according to a security official said.
On February 17, a suicide bombing claimed by IS killed 14 soldiers.
The rebels controlled Aden for months before government loyalists pushed them out in July.
Because of the unrest gripping Aden, Hadi himself and many senior officials in his government spend most of their time in Riyadh.