GAZA — Israel carried out more airstrikes in Gaza early Friday, accidentally killing a Palestinian man and his 12-year-old son as militants continued to fire rockets into southern Israel.

Tensions flared after an Israeli airstrike in Gaza City on Thursday killed two Palestinians whom the military described as terrorists involved in a plot to attack Israelis. Palestinians retaliated by firing rockets from Gaza into southern Israel.

The Palestinian man who was killed on Friday died instantly when Israeli fighter jets attacked at least two targets that were described as training sites for the armed wing of Hamas, the Islamic militant group that controls Gaza. The boy died later of his wounds, and seven family members, including two women and several other children, were injured. The man was identified by Agence France-Presse as Bahjat al-Zalan. One of the strikes, on a site in northern Gaza, badly damaged a house, causing the casualties, said Adham Abu Selmia, a spokesman for the Gaza medical services.