“This is a humanitarian catastrophe,” Gabriel Karlsson, Middle East Manager at the British Red Cross in Beirut, told the BBC.
He said there are insufficient shelters to accommodate so many evacuees.
“I saw children sleeping in the streets,” Karlsson added, urging humanitarian organisations to coordinate their efforts to address the escalating crisis.
Lebanese officials say at least 2,350 have been killed and over 10,000 injured in Israeli attacks. The Lebanon health minister said many casualties were civilians.
On the Israeli side, 60 people have been killed and more than 570 wounded by Hezbollah attacks, Israeli authorities say.
“Collateral damage is inevitable in war”, Amos Yadlin, the former head of Israeli military intelligence, told the BBC.
The retired major-general blamed Hezbollah for the war and claimed Israel’s ground offensive would force the group out from the border areas.
Zwijnenburg, from the Pax for Peace organisation, however, has warned of the impact of Israel’s military campaign on civilians and the populated areas.
“The heavy blast radius kills and maims civilians nearby”, he said, in reference to Israeli air strikes.
“Open-source data combined with satellite imagery also showed that civilian infrastructure such as irrigation channels, gas stations and electricity grids were damaged, which is worsening the humanitarian situation,” he added.
Additional reporting by Paul Cusiac and Maria Rashed
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