An attack on a cattle market in northeastern Nigeria by gunmen armed with explosives has left at least 34 dead and the toll is likely to climb, an emergency source said on Thursday.

"Thirty-four bodies were deposited at the hospital," the official said on condition of anonymity of the attack late Wednesday in Potiskum because he was not authorised to speak publicly. He said the toll was likely to be more than 50 dead because families were also burying relatives' bodies without bringing them to the hospital.