The pregnant wife of a pastor has been killed after being abducted by armed assailants from her home in Kaduna state, central Nigeria, last month.
Esther Katung was seized by armed men believed to be from the Fulani ethnic group at around 11:45pm on 14 September.
Her husband, the Rev Ishiaku Katung, minister of the Evangelical Church Winning All Prayer House in Birnin Gwari Local Government Area, was injured in the attack.
Her kidnappers had demanded N5000000 (around US$13850.00) in exchange for her release before agreeing to a payment of N400000 (around US$1105.00).
But before the money was received by the captors, other hostages who were released reported that Mrs Katung had died as the result of a severe beating.
Mervyn Thomas, chief executive of Christian Solidarity Worldwide, said he was "appalled" by the attack on Mrs Katung.
"CSW offers our deepest condolences to the family and loved ones of Mrs Katung. We are appalled and saddened by the cruelty of her abductors and the tragic circumstances in which she died," he said.
CSW reports that there has been an increase in kidnappings for ransom across Nigeria. Church leaders and their families in Kaduna are being especially targeted, it said, but brutal attacks have occurred elsewhere, with three Catholic priests recently being killed in abductions and attempted abductions in Enugu Diocese in the south.
The organisation said that "well-armed" assailants suspected to be Fulani were behind the abductions.
Mr Thomas said: "Given that the Nigerian constitution asserts that the 'security and welfare of the people' are 'the primary purpose of government,' we urge the authorities to do everything in their power to safeguard citizens and bring perpetrators to justice."
Nigeria has struggled to contain the spread of terrorism. In another sign of the ongoing threat, the Islamic State West Africa Province, an offshoot of the so-called Islamic State, released a video last month showing the execution of two Christian aid workers, Lawrence Duna Dacighir and Godfrey Ali Shikagham, who were both from Plateau state and members of the Church of Christ in Nations (COCIN).
They were beheaded by the terrorists who warned that the murders were the beginning of "revenge on Christians in Plateau state" for allegedly killing their women and children, and eating their meat.
"The video provides the first clear indication of a link between the terrorist organisation and the militia violence that has affected communities in Plateau and other central states," CSW said.
Another video released late last month showed one of six Action Against Hunger workers abducted in Borno state in July being executed by the terrorist group.
Mr Thomas continued: "We also extend our deepest condolences to the families of these three young men. The fact that in one of these cases the terrorists cited the victims' state of origin as well as their religion is particularly concerning as it raises the possibility of coordination or cooperation between two sources of terrorist violence.
"We urge the Nigerian government to ensure the armed forces are sufficiently equipped to address the threats posed by both ISWAP and the Fulani militia, and call on the international community to assist Nigeria wherever possible in this regard."