Human Rights Watch warned on Wednesday that Israeli strikes on Lebanon were putting civilians "at grave risk", urging an international investigation into attacks on the country.
Israeli raids on Lebanon on Monday killed at least 558 people, in the deadliest day of violence since Lebanon's 1975-1990 civil war, while Hezbollah has been firing barrages of rockets towards northern Israel, sending civilians running for shelters, including in the northern city of Haifa.
"More than 1,000 Israeli strikes across Lebanon that have killed hundreds of people and injured thousands" this week "are placing civilians across the country at grave risk of harm", HRW said in a statement.
United Nations "member states should take urgent action to establish an independent inquiry into violations during the current hostilities", said Lama Fakih, HRW's Middle East and North Africa director.
"It is paramount for Israel and Hezbollah to comply with the laws of war to minimise civilian harm," Fakih said in the statement.
"The presence of a Hezbollah commander, rocket launcher, or other military facility in a populated area does not justify attacking the area without regard to the civilian population," Fakih added.
Since Monday, the UN's International Organization for Migration has recorded some 90,000 newly displaced people in Lebanon.
On Tuesday, the International Rescue Committee said it was "deeply concerned by the escalating conflict in Lebanon", adding that "ongoing insecurity may significantly hinder our ability to deliver vital assistance to those in need".
On Monday, the Norwegian Refugee Council urgently appealed "for immediate de-escalation by all parties to the conflict and for an end to the indiscriminate attacks that destroy civilian homes and infrastructure".
"The targeting of civilian areas in southern and eastern Lebanon and northern Israel escalates hostilities to a new and incredibly dangerous level," a statement said.