The woman who the British High Commission identified as Faye Mooney was among two people shot dead as the armed kidnappers stormed a party at a holiday resort late on Friday.
The armed gang also killed a Nigerian man and reportedly kidnapped three others after gaining entry to the Kajuru Castle Resort in Kaduna State.
Ms Mooney was employed in Nigeria as a communication specialist for the non-governmental organisation Mercy Corps, which said it was “utterly heartbroken”.
A Mercy Corps statement said Ms Mooney, who was working in Nigeria, was “tragically killed” by gunmen while on holiday in the northern city of Kaduna.
Kidnapping for ransom is common in Nigeria, with foreigners and high-profile Nigerians frequently targeted.
Neal Keny-Guyer, Mercy Corps chief executive, said she had worked with the company for almost two years “leading efforts to counter hate speech and violence” in Nigeria.
He said the graduate of University College London and the London School of Economics, who had previously worked in Iraq and Kosovo, was “an inspiration to us all”.
Police said there had been no claim of responsibility for the incident and the kidnappers were yet to be identified.
A spokesman said a group armed with dangerous weapons had gained entry to Kajuru Castle and began shooting sporadically, killing two people and kidnapping three others.
See Ms Mooney’s photos below.
Photos from inside the Resort.