In the Israeli strike on Sunday morning, it took emergency workers and a Caterpillar digger more than an hour to reveal the extent of the devastation under the two-story home of Jamal Dalu, a shop owner. Mr. Dalu was at the market when the blast wiped out nearly his entire family: His sister, wife, two daughters, daughter-in-law and four grandchildren ages 2 to 6 all perished under the rubble, along with two neighbors, an 18-year-old and his grandmother.

Ismail Haniya, the prime minister of the militant Hamas faction that rules Gaza, condemned the attack as a “massacre” that “exceeded all expectations.”

General Mordechai, the spokesman for the Israeli military, said it was “examining the event.”

“The wanted target in this case was responsible for firing dozens of rockets into Israel,” he added. “I do not know what happened to him, but I do know that we are committed to the safety of the citizens of Israel.”

The Dalu family were buried Monday after an intense, chaotic two-hour funeral procession that quickly became a Hamas rally clearly aimed at least in part at sending a strong message of defiance through the scores of journalists in the crowd. Thousands thronged the streets following the bodies from the destroyed Dalu home to the Esraa Mosque and then to the Sheikh Radwan cemetery, shouting slogans of resistance as fighters fired rifles into the air and waved the green Hamas flags as well as the white ones of the armed Al Qassam Brigades.

Outside the cemetery, a Qassam leader named Mosheer Al Masri spoke not about the victims but about the enemy.