The UN Human Rights Commissioner Volker Türk calls the escalation "completely and utterly unacceptable" and demands an end to the "bloodbath".
The whole world is screaming for peace. Palestinians and Israelis are screaming for peace, he says.
He receives support from the UK's Foreign Minister Yvette Cooper, who calls it "completely reckless and appalling".
"It will only create more bloodshed, kill more innocent civilians and put the remaining hostages in danger", she writes on X.
The escalation will worsen an already "catastrophic" humanitarian situation in the Gaza Strip, emphasizes the EU Commission's foreign spokesperson Anouar El Anouni.
