Nominated BBMP councillor J. William, 40, was attacked by four armed men when he stepped out of his office at Kadugondanahalli on Tuesday night.
The councillor sustained head injuries. He was taken to a private hospital. He is said to be out of danger.
The alleged incident occurred around 8.30 p.m. According to the police, the assailants wore helmets to cover their faces and were armed with knives.
As news of the attack spread, hundreds of people gathered in front of the BBMP office demanding that the attackers be arrested as soon as possible .
“The reason for the attack is not clear,” a senior police officer said. The police have registered a case of attempt to murder.