A group calling itself the Nigerian Cyber Army hacked into and shut down the electoral commission's website on Saturday, warning officials not to rig the presidential election as accreditation for voting in the poll was under way.
"Strucked by Nigerian Cyber Army," read the banner at the top of the page, and underneath: "security is just an illusion."
The Independence Electoral Commission (INEC) said in a tweet that it was aware of the hack and investigating it, although with about 120,000 polling stations to manage and major technological problems with biometric card readers, its resources are stretched.
The disabling of the website was not seen as interfering with the voting process.
The page featured a picture taken from a newspaper of candidates Muhammadu Buhari and President Goodluck Jonathan as football players and INEC chairman Attahiru Jega as referee warning them against "post match hooliganism".
"If you attempt to rig, you will pay," the message read.
Government websites are periodically hacked by ingenious Nigerians making use of creative grammar and punctuation to leave embarrassing messages.
© Thomson Reuters 2015