The EU's top diplomat Josep Borrell on Monday described Israel's “lack of distinction” between civilians and military targets as “appalling".
His comments come as the US, the UK, Germany and France increase pressure on Israel to tone down its bombardments on the Gaza strip as the death toll nears 20,000.
“Certainly, we are witnessing an appalling lack of distinction in Israel's military operation in Gaza,” wrote Mr Borrell on X.
Mr Borrell pointed at reports on Sunday of an Israeli soldier shooting dead two Christian women, an elderly mother and her daughter, in the grounds of a Catholic church in Gaza city.
He also highlighted the recent killing of three Israeli hostages – shirtless and waving a white flag – by Israeli soldiers who ignored orders not to fire, according to the Israeli army.
“This must stop – a humanitarian pause is urgently needed,” said Mr Borrell.
Mr Borrell speaks on behalf of the EU's 27 member states. In late October, its leaders agreed on a call for “humanitarian corridors and pauses for humanitarian needs” but failed to update that language at a meeting in Brussels on Friday.
Though a majority of countries including France and Spain had said the bloc should unite behind a call for a ceasefire, EU heavyweight and staunch Israeli ally Germany remains hesitant.
EU leaders however tasked Mr Borrell to draw up a list of violent Israeli settlers for discussions on banning them from Europe.
“Measures will be taken” against them, said French Foreign Affairs Minister Catherine Colonna during a visit to Israel and Palestinian territories on Sunday.
Attacks by extremist settlers on Palestinians in the occupied West Bank are widely viewed as hindering a two-state solution to the conflict.
Ms Colonna also reiterated France's call for an “immediate and durable” truce in Gaza.
“France could play a positive and crucial role in preventing a war in Lebanon,” her Israeli counterpart Eli Cohen said at a joint press conference.
There are parallel discussions among European leaders to crack down on Hamas networks. Arrests were announced by Germany last week.
Ms Colonna is scheduled to land in Beirut on Monday in a bid to de-escalate the Israel-Gaza war.
France, a former colonial power in the region, is worried about the conflict spilling over in Lebanon, a country in which Paris is more diplomatically invested than any other European country.
As outrage grows over human suffering in Gaza, Germany slightly shifted its position over the weekend.
The World Health Organisation, which reached Gaza’s Al Shifa hospital on Sunday, described it as resembling a “bloodbath.”
German Foreign Minister Annalena Baerbock co-signed a letter with UK Foreign Secretary David Cameron in The Sunday Times calling for a “sustainable ceasefire”.
This differed from the French request for an immediate ceasefire.
The UK and Germany said Israel should be allowed to press on with its military objective of eliminating Hamas from Gaza.
But they also asked Israel to “do more to discriminate sufficiently between terrorists and civilians” and allow more aid to reach “ordinary Palestinians”.
During a visit to Israel on Monday, US Secretary of Defence Lloyd Austin is expected make the case to Israeli military leaders that they should be changing tactic within weeks.
Israel needs to shift to more precise targeting of Hamas, US National Security Adviser Jake Sullivan said on Friday.
Some observers predict Israel will not be able to resist global opinion much longer.
“We're getting closer to the point where they're going to have to conclude they need have to change their military tactics,” retired senior British diplomat Peter Ricketts told the BBC.
