JERUSALEM (AP) — Israel’s military operation in the Gaza Strip is expanding to seize “large areas,” the defense minister said, while officials at hospitals inside the Palestinian territory said that Israeli strikes overnight and into Wednesday had killed more than 40 people, nearly a dozen of them children.

The U.N. has said Israel killed the workers. The video appears to contradict Israel’s version of the incident, which described the vehicles as “advancing suspiciously” without headlights or emergency signals.

Israeli Defense Minister Israel Katz announced Wednesday a major expansion of the military’s operation in Gaza involving the seizure of large areas of land that would be “incorporated into Israel’s security zones.

The Israeli military has indicated it could soon launch another major offensive in Rafah and ordered most of the southernmost city in the Gaza Strip evacuated.

Aid agencies say the workers were killed and buried in a mass grave in Rafah in southern Gaza. Residents described being shot at along the evacuation route.

In pressing forward with its assault on the territory, Israel hopes to squeeze Hamas into releasing the remaining hostages. But other objectives have emerged.

As Israel orders wide new evacuations across the Gaza Strip, Palestinians say they are crushed by exhaustion and hopelessness at the prospect of fleeing once again.