Gunmen have shot dead a 65-year-old Italian nun and her bodyguard at a hospital in Somali capital, Mogadishu.
Sister Leonella had worked in both Somalia and Kenya
The attackers shot the nun three times in the back at the women and children's hospital in the south of the city before fleeing the scene.
It is unclear if the shooting is connected with strong criticism by a radical Somali cleric about the Pope's recent comments on Islam.
Sister Leonella had worked in Africa for nearly 40 years, her family said.
She was taken into surgery in the Austrian-funded SOS Hospital, in Huriwa district, but she died from her injuries.
A fluent Somali-speaker, the nun was one of the longest-serving foreign members of the Roman Catholic Church in Somalia, a former Italian colony.
A Vatican spokesman said the killing was "a horrible act" which he hoped would remain isolated.
Yusuf Mohamed Siad, security chief for the Union of Islamic courts (UIC) which controls Mogadishu, said two people had been arrested.
Pope Benedict XVI inflamed many Muslim communities last week after making comments during a speech in Bavaria.
He quoted a 14th Century Christian emperor as saying the Prophet Muhammad brought the world only evil and inhuman things.
The Pope has since apologised in person, saying his remarks were misunderstood and did not express in any way his personal opinion.
On Friday, hardline cleric Sheikh Abubakar Hassan Malin told worshippers at his mosque to hunt down and kill whoever offended the Prophet Mohammed.
There has been no effective central government in Somalia since 1991, and although the UIC is credited with bringing some stability to Mogadishu, correspondents say the city is far too dangerous for all but the bravest aid workers to operate in.