(CNN) -- A large explosion left 40 injured and destroyed the house of a Palestinian militant leader in central Gaza early Monday morning, authorities said.
It was not clear what caused the blast at the home of Qassam leader Ala Danaf in Deir al-Balah.
Of the dozens of injuries, four were serious, said Moawia Hasanain, director of medical emergency in Gaza.
"Most of the injured were women, children and elderly," Hasanain said. "This is a serious Israeli violation and a clear daily escalation, and this reveals the real Israeli intentions."
The Israeli military said it had no activity in Gaza overnight.