Israel stepped up its assault on Gaza City over the weekend, killing at least 45 people and leveling residential buildings, as Prime Minister Benjamin Netanyahu’s security cabinet prepared to discuss plans to seize the city.

Local health officials told Reuters at least 30 people were killed Sunday, including 13 who were trying to collect food near an aid site in central Gaza and two in a home in Gaza City. A separate strike on Saturday killed 15 people, among them five children.

The Israeli military said it was reviewing the reports, adding it takes steps to minimize civilian casualties while targeting militants.

Netanyahu has called Gaza City the “last bastion” of Hamas, and his cabinet is set to debate the next phase of a planned offensive on Sunday. A full-scale operation is not expected for weeks, with Israel insisting it intends to evacuate civilians before sending in more ground troops.

Meanwhile a pro-Palestinian flotilla departed Barcelona for Gaza on Sunday, aiming to “break Israel’s illegal siege,” organizers said.

The Global Sumud Flotilla set sail at around 3:30 p.m. with activists and supporters on board, including Swedish climate activist Greta Thunberg.

“Israel [is] very clear about their genocidal intent. They want to erase the Palestinian nation. They want to take over the Gaza Strip,” said Thunberg, hitting out at politicians and governments for “failing to uphold international law.”

“They are failing to do their most basic, legal duties to act, to prevent a genocide, to stop their complicity and support for … the occupation and the genocide of Palestinians,” she said.