EU chief Ursula von der Leyen called on Israel on Friday to reverse its plan to occupy the Gaza Strip.
"The Israeli government's decision to further extend its military operation in Gaza must be reconsidered," she said on X.
She also urged the release of all captives and "immediate and unhindered access" to humanitarian aid in Gaza. "A ceasefire is needed now," von der Leyen said.
The bloc has struggled to take action over the war in Gaza as it is split between staunch supporters of Israel - like Germany - and those more favourable to the Palestinians, such as Spain.
The EU's top diplomat Kaja Kallas last month put forward a raft of options to punish Israel after it was found guilty of breaching a cooperation deal with the EU on human rights grounds.
Brussels has since proposed suspending Israel's access to EU funding for tech start-ups, which member states have yet to approve.
The European Union also struck a deal last month to increase aid access to Gaza, but senior officials have said that it has been only partially implemented.
Germany on Friday dramatically changed course when it said that it would halt the export of military equipment to Israel which could be used in the Gaza Strip.
Meanwhile, Belgium announced on the same day that it was summoning the Israeli ambassador to express its "total disapproval" of Israel's plans to take military control of Gaza.
The tone appears also to be shifting in Brussels.
European Commission Vice President Teresa Ribera said that Israel's approach "looks very much" like a genocide, in comments to the Politico portal published on Thursday, referring to people starving, displaced and killed in war-torn Gaza.