(CNN) -- Seven people who were on the roof of a home in Khan Younis, Gaza, were killed in an Israeli airstrike Tuesday, according to Palestinian medical sources. Earlier, the sources said 10 were killed. The home belonged to a family associated with Hamas' military wing, and the seven were trying to form a "human shield" on the roof a day after an Israeli airstrike destroyed an adjacent home belonging to the same family, Palestinian medical and security sources said.