Fire brigade officials received a call about the blaze at Himalaya Estate Building in the city's Shivajinagar area around 3 am today.
"Upon reaching the spot, it was found that the fire had broken out inside a printing press-cum-paper box manufacturing unit in building," a fire brigade official said.
"Since the unit was closed, we broke open its shutters," he said.
The bodies of two labourers, who were sleeping inside the unit, were later recovered from the site, the police said.
Seven fire tenders were pressed into action to douse the flames, he said, adding that the cooling work was still on.
A short-circuit possibly led to the blaze, but the exact cause was yet to be ascertained, he said.
An investigation was on into the incident.
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