Three sons and three grandchildren of Hamas ’ top political leader were killed Wednesday by an Israeli airstrike in the Gaza Strip, and the leader accused Israel of acting in “the spirit of revenge and murder.”

In his interview with Al Jazeera, Haniyeh said the killings would not pressure Hamas into softening its positions.

“The enemy believes that by targeting the families of the leaders, it will push them to give up the demands of our people,” he said. “Anyone who believes that targeting my sons will push Hamas to change its position is delusional.”

“The criminal enemy is driven by the spirit of revenge and murder and does not value any standards or laws,” he said in the phone interview.

The strike came as Palestinians in Gaza marked a muted Eid al-Fitr holiday, which ends the holy fasting month of Ramadan, by visiting the graves of loved ones killed in the war.