An airstrike on Gaza City killed at least 12 people as the conflict entered a new phase with an Israeli offensive to rid the city of Hamas and free hostages.

JERUSALEM (AP) — Israel said Friday it will intensify its 22-month war with Hamas by taking over Gaza City, stirring fears for Palestinian civilians and Israeli hostages still held in Gaza, and renewing international pressure for an end to the conflict.

The U.N. High Commissioner for Human Rights, Volker Turk, said “this further escalation will result in more killing, more unbearable suffering, senseless destruction."