Personnel records of former and current members of Nigeria's State Security Service, the country's top domestic spy agency, have been leaked onto the internet.
A radical Islamist sect said to have killed hundreds of people this year alone has claimed responsibility.
The data include home addresses and the names of immediate family members of the spy agency employees.
The personal data of the more than 60 past and current employees of the agency was easily accessible on the internet for days.
It contains details about the agency's director-general, including his cellphone number, bank account particulars and contact information for his son.
Many of the agents listed who could be reached said they had received no warning from the spy agency that their information had been posted online.
The security breach calls into question whether Nigeria's intelligence community, because it is so deeply infiltrated, will be able to limit the Islamist violence now plaguing Africa's most populous nation.
Marilyn Ogar, a spokesman for the agency, did not respond to requests for comment yesterday. Though geared towards stopping terrorism and coup plots, the agency routinely faces criticism for targeting government critics.
The first posting threatened the agents would be killed by Boko Haram, a radical Islamist sect responsible for more than 660 killings this year in Nigeria.
The second offered a block of text containing biographical and other details about the agents.
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