Foreign Secretary William Hague said he is determined to track down the terrorists behind the apparent killing of a British hostage.
"Responsibility for this tragic outcome rests squarely with the terrorists. I am grateful to the Nigerian Government for their unstinting help and co-operation," he said.
"We are utterly determined to work with them to hold the perpetrators of this heinous act to account, and to combat the terrorism which so blights the lives of people in Northern Nigeria and in the wider region."
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Monica O'Connor and at least two other people were killed in the incident, and a British man remains missing.
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