Authorities in Yemen blamed "Islamic State" militants for an attack on a nursing home that killed 16 people. More than 6,000 people have been killed in the country since a civil war broke out there 18 months ago.
Pope Francis condemned a massacre at an nursing home in Yemen that included the murders of four nuns as "diabolical."
No one has claimed responsibility for the attack but local al-Qaeda militants have denied responsibility for the assault, and government authorities have blamed the "Islamic State" (IS).
The Vatican's Secretary of State Pietro Parolin said, "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.
"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," Parolin said in a statement.
Screams of elderly residents echoed from the home during the shooting rampage, according to witnesses recounting seeing the bodies of slain workers with their arms tied behind their back.
The nuns were identified as two Rwandans, a Kenyan and an Indian. The Vatican missionary news agency, Fides, reported that the mother superior managed to hide and survived the attack. An Indian doctor is missing.
Yemen's civil war
Yemen has been torn apart by a civil war since 2014.
Iranian-backed Houthi rebels overran Yemen's capital, Sanaa, in September 2014, forcing the government into exile in Saudi Arabia.
Although a provisional capital has been established in Aden, the government has struggled to impose its authority even there. IS militants, al Qaeda fighters and Houthi rebels are all battling government forces for control of the country.
Al-Qaeda in the Arabian Peninsula, also known as Ansar al-Sharia, denied "any links to the attack on the elderly care home."
In a statement addressed to the residents of Aden, the group said, "These are not our operations, and this is not our way of fighting."
Al-Qaeda, which has seized parts of southern and eastern Yemen, has previously criticized IS for attacks on Shiite mosques in the country that killed dozens.
The violence has escalated in Yemen, with more than 6,000 people killed since a Saudi-led coalition launched a campaign of airstrikes one year ago.
Yemeni security officials said Saturday that the head of police in the Tawahi district of Aden was killed along with two of his guards in an attack by suspected Islamic militants.
Also on Saturday, President Abedrabbo Mansour Hadi discussed the stalled peace process with UN envoy Ismail Ould Cheikh Ahmed in Riyadh.
"Goodwill gestures and confidence-building measures by releasing detainees, lifting the siege on cities, and opening safe corridors to deliver humanitarian assistance to besieged provinces... are necessities that must be met" by the rebels, Hadi told the UN envoy.
bik/sms (AFP, AP, Reuters)