- Dozens of people may still be trapped in the factory's basement
- Firefighters are battling to bring the blaze under control
- At least 25 people have been injured by the fire, a rescue official says
- Fire officials say they don't yet know the cause of the fire
Islamabad, Pakistan (CNN) -- At least 55 people, including a child, were killed in a fire that swept through a garment factory overnight in the Pakistani city of Karachi, a rescue official said Wednesday.
At least 25 people have been injured by the fire, which continued burning Wednesday morning, said Zakir Khan, of the Karachi Fire Department. All the victims were employees of the factory, he said.
Firefighters were trying to bring it under control.
Dozens of people may remain trapped in the basement of the building, according to Khan. A rescue operation is under way to try to save them.
Several workers who were trapped by the fire jumped out of the upper floors.
Video broadcast by CNN affiliate Geo TV showed large crowds of anxious people gathered outside the smoldering building.
Through windows and holes of the scorched outer walls of the factory, the video footage showed glimpses of flames still flickering within.
Fire officials say they don't know the cause of the fire at this point.
Journalist Aamir Iqbal in Peshawar, Pakistan, and CNN's Jethro Mullen in Hong Kong contributed to this report.
