Gunmen threw bombs and opened fire on a cattle market in northeastern Nigeria, killing at least 60 people, a spokesman for the Yobe state governor said.
"The Yobe State Governor has visited the Potiskum cattle market where he was informed that 60 people had been killed in the attack, while 29 people are receiving treatment at the hospital," Abdullahi Bego, spokesman for Governor Ibrahim Gaidam, said.
It was not clear who was behind the attack overnight on Wednesday in the town of Potiskum in the country's northeast.
Some reports suggested that robbers angered by a crowd burning one of their colleagues alive earlier in the day had attacked the cattle market in retaliation.
There was no immediate claim of responsibility for the attack.
A hospital nurse said he had counted 56 bodies at the Potiskum morgue.
"I am sure that the death toll could rise in view of the serious nature of injuries sustained," the nurse at Potiskum
hospital, Babangida, said. "The Potiskum mortuary is made up of a room and a parlour and I counted the 56 in the parlour only. I didn't go into the inner room."
Describing late Wednesday's attack, Toyin Gbadegesin, a police spokesman, said: "A group of gunmen armed with around 20 explosives and assault rifles attacked the Potiskum cattle market.
"They threw explosives and shot indiscriminately, setting fire to the market, killing lots of livestock and wounding many people, mostly cattle dealers."
Witnesses said the violence began earlier in the day when gunmen started shooting at the market in Potiskum, a city 575km northeast of Nigeria's central capital, Abuja.
Three people were killed in the ensuing gunfire, which ended when the attackers ran out of ammunition.
All but one of the gunmen escaped.
Those gathered in the market beat the gunmen left behind before dousing him in gasoline and lighting him on fire.
As the market closed for the night, the gunmen returned, setting fire to cattle holding pens and cars parked around the area.
By Thursday morning, only the metal skeletons of cars and the burnt ashes of the pens remained on the arid soil.
Dead cattle, apparently hacked to death by attackers with machetes, lay atop the charred ground.
Residents crowded a local hospital to determine if their relatives were among the dead.
Gangs often seek to provoke panic at markets, forcing traders to flee so they can steal their wares.