GAZA/JERUSALEM — Israeli airstrikes killed at least 78 people in Gaza, Palestinian health officials said on Sunday, in one of the besieged enclave's deadliest nights of the 11-week-old conflict.

Strikes that began hours before midnight continued into Monday. Residents and Palestinian media said Israel stepped up air and ground shelling in Al-Bureij in central Gaza.

At least 70 Palestinians were killed on Sunday in an Israeli airstrike on the al-Maghazi refugee camp in central Gaza, reported the state-run Palestine TV.

Ashraf Al-Qedra, spokesman for the Gaza-based Health Ministry, said in a statement that the death toll is likely to rise as the airstrike hit a crowded residential area. He added that Israeli forces are bombing the central region's main roads between camps, which obstruct ambulances and civil vehicles from reaching targeted locations.

Al-Maghazi was one of the places the Israeli military had previously told the Palestinians in Gaza to evacuate to, yet the camp has been "completely flattened," according to Al Jazeera.

The Israeli army said it was reviewing the report on the al-Maghazi camp and was committed to minimizing harm to civilians. Hamas denies the Israeli charge that it operates in densely populated areas or uses civilians as human shields.

The Palestine Red Crescent Society published footage of wounded residents being transported to hospitals. It said Israeli warplanes were bombing main roads, hindering the passage of ambulances and emergency vehicles.

Medics said an Israeli airstrike in Khan Younis in southern Gaza killed eight Palestinians.

Prime Minister Benjamin Netanyahu told his cabinet on Sunday that "the war is exacting a very heavy cost from us. However, we have no choice (but) to continue to fight."

He said in a video message that troops would fight deeper into Gaza until "total victory" over Hamas.