Heavy casualties were feared on Tuesday after a suicide attack at a busy cattle market in the northeast Nigerian city of Maiduguri, civilian vigilantes battling Boko Haram told AFP.

The blast in the Borno state capital happened at about 1:00 pm (1200 GMT) as traders ended business for the day, said Shettima Bulama in an account backed up by another local vigilante.

"We're trying to sift human bodies from carcasses of cattle that are strewn all over the place... I can't give you a death toll now but we should expect high casualties," he said.