The attack late Thursday in the Yobe state capital of Damaturu was the first raid in a major urban centre in several weeks.
"We have received lots of bodies in the last three days from the attacks. I counted 35 bodies in military uniform," a senior official at the Damaturu Specialist Hospital, who requested anonymity, told AFP.
The military rarely discusses troop fatalities following Islamist attacks and local officials who disclose death tolls among the security forces have faced pressure to keep quiet.
"We do not have any data on the death toll," Lazarus said.
Boko Haram has repeatedly worn military uniforms as a disguise during attacks and it was not yet clear if the corpses were those of insurgents or troops.
The day after the attack, witnesses and local officials did not say the insurgents who staged it were disguised in uniforms.