The alleged gas leak happened on Saturday night, media reported, adding that all those injured had been taken to nearby hospitals, with four of them in serious condition.
"There was an explosion. Possibly due to a gas leak. The exact causes of what happened will be determined by the investigation," Massimo Bambini, mayor of the town of San Lorenzo Nuovo that hosts the migrant reception center, told media.
In total, around 30 people, including minors, were inside the building at the moment of the explosion, according to initial information, but firefighters working at the scene have ruled out the presence of other people under the rubble, the news agency reported.