Pope Francis has slammed as "diabolical" an attack on an elderly care home in Yemen which killed at least 16 people, including four nuns, the Vatican said Saturday.
"His Holiness Pope Francis was shocked and profoundly saddened to learn of the killing of four Missionaries of Charity and 12 others at a home for the elderly in Aden," the Vatican's Secretary of State Pietro Parolin said.
"He sends the assurance of his prayers for the dead and his spiritual closeness to their families and to all affected from this act of senseless and diabolical violence," Cardinal Parolin said in a statement.
Four gunmen stormed the facility housing dozens in Aden's Sheikh Othman district on Friday, killing a guard before tying up and shooting employees, security officials told AFP.
Screams of elderly residents echoed from the home during the shooting rampage, witnesses said. Among the dead were four Indian nurses, while the rest of those killed were Yemenis.
The Argentine pontiff "prays that this pointless slaughter will awaken consciences, lead to a change of heart, and inspire all parties to lay down their arms and take up the path of dialogue," Parolin said.
"He calls upon all parties in the present conflict to renounce violence, and to renew their commitment to the people of Yemen, particularly those most in need, whom the sisters and their helpers sought to serve," he added.
No group claimed responsibility for Friday's 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 Islamist insurgency presence on the other.
One official said the attackers were "extremists" and blamed the Islamic State group, which has been gaining ground in Aden in recent months.
The six-nation Gulf Cooperation Council backing the Yemeni government "strongly" condemned the attack which it said "reveals the goals of forces which are against the return of security and stability to Yemen".
President Abd Rabbo Mansour Hadi has declared Aden Yemen's temporary capital as Sanaa remains in the hands of the Houthi rebels and their allies since they seized it in September 2014.