(CNN) -- Thirty-four people were killed and 30 wounded in an attack on a cattle market in Nigeria's northern Yobe state, a government official briefed on the investigation said Thursday.
The attack Wednesday evening appears to have escalated from an initial raid on the market by two suspected robbers, one of them armed, said the official, who did not want to be named for security reasons.
The market traders eventually overpowered the man with the gun and beat him severely before burning him with tires, the official said.
This appears to have angered allies of the two robbers, who then attacked the market with grenades and sporadic shooting, the official said. He noted that the tactics used were similar to those of the militant Islamist group Boko Haram.
The governor of Yobe is believed to be on his way to the market to see the level of damage, the official said.
The official said a member of the Cattle Market Owners' Association had told him he counted 60 bodies Friday morning, most of which have been collected by their relatives for burial.
Nigeria has suffered a string of violent attacks, many of them sectarian in nature, in recent months.
A suicide attack Monday in northeastern Taraba state killed 11 people and wounded another 26, a spokesman for the Nigerian Red Cross said. The attack appeared to target a police commissioner.
And at least eight people were killed, including a suicide bomber, and dozens wounded last Thursday in three bomb blasts in central and northern Nigeria, two of them targeting newspaper offices.