Khaled Mansour, the slain militant commander, was behind a string of attacks, the Israeli military said.

Khaled Mansour, the Islamic Jihad militant commander who was killed in an Israeli missile strike in southern Gaza on Saturday night, was responsible for rocket and mortar attacks against Israel stretching back years, according to the Israeli military.

Mr. Mansour, who led the militant group’s operations in the southern region of Gaza, held a rank equivalent to that of a general, the Israeli military said. It added that he had claimed responsibility for an attack that killed two Israeli soldiers in 2010 and was involved in another attack that injured the Israeli commander of the Southern Gaza Brigade in 2004.

One of the soldiers killed in 2010, Maj. Eliraz Peretz, is almost a household name in Israel. His mother, Miriam Peretz, who lost two sons in uniform in two separate enemy actions, has become a national symbol of sacrifice.

Mr. Mansour’s body was pulled from the rubble of a collapsed building in a refugee camp in Rafah, in the southern Gaza Strip, along with the bodies of his deputy and another militant and five civilians, including a child, according to Islamic Jihad.

The militant group mourned their deaths in a statement and vowed to retaliate with more rocket attacks. Surviving leaders of Islamic Jihad attended funerals on Sunday for those killed.

Israeli military officials said they regretted civilian deaths in Gaza and pledged that they would be investigated. But they have blamed the militants for operating out of residential neighborhoods and using Gaza residents as “human shields.”

The military also claimed that Mr. Mansour had been plotting an attack against Israel using anti-tank missiles and rockets.

The assassination of Mr. Mansour followed the killing of Islamic Jihad’s commander for the northern region of Gaza, Taysir al-Jabari, in Israeli strikes on Friday that opened the latest flare-up in fighting. Israel said the strikes had thwarted the group’s plans for an anti-tank missile attack along the border to avenge the arrest of a senior Islamic Jihad commander in the West Bank.

Fady Hanona contributed reporting from Gaza City.