The Israeli military said it had targeted and destroyed buildings used to store rockets and munitions belonging to the Palestinian militant group Islamic Jihad.
The residents said eight bystanders were wounded in the strikes on houses in Gaza City and the towns of Khan Younis and Rafah in the southern part of the coastal territory.
Israel has killed 121 Palestinians in a month-long offensive in Gaza designed to recover a soldier captured by militants from the ruling Hamas movement on June 25. The military is also trying to stop militants from firing rockets into Israel.
The military said it had warned residents to leave the buildings before the strikes to try to avoid civilian casualties by distributing leaflets from the air and through telephone calls directly to the house owners.
On Monday, Israeli shells killed six people and wounded several others in the Gaza Strip, Palestinian witnesses said.