Hospitals in Gaza said at least 21 Palestinians were killed in Israeli strikes Wednesday on both sides of the yellow line established in last month’s ceasefire. The boundary splits the enclave in two, leaving the border zone under Israeli military control while the area beyond it is meant to serve as a safe zone.

The escalation comes as Israel falls short of its ceasefire obligation to withdraw from the south, with forces remaining at five border outposts.

An airstrike killed 13 people in the Palestinian refugee camp of Ein el-Hilweh. It was the deadliest Israeli attack reported since a ceasefire in the Israel-Hezbollah war a year ago.