Christian Aid has reiterated calls for an immediate ceasefire in Lebanon, after Israel struck Hezbollah militant targets in the country.
The Israeli Defence Force (IDF) had ordered the evacuation of around a sixth of Lebanon, following Hezbollah firing missiles across the border.
The latest evacuation order covers around nine square miles (23 square km) of the Lebanese capital Beirut, comparable in size to the borough of Tower Hamlets in London or the town of Windsor in Berkshire.
More than 600 people have been killed since Israeli strikes began, according to Christian Aid.
The relief and development charity is warning of a “deepening” humanitarian crisis in Lebanon.
Israeli foreign minister, Gideon Sa’ar, denied reports on Sunday that officials in Jerusalem and Beirut were going to hold talks.
William Bell, Christian Aid’s head of Middle East policy and advocacy, said: “Imagine an area roughly the size of Windsor being ordered to evacuate because every building is at risk of being hit by an Israeli air strike. That's the reality facing hundreds of thousands of people living in southern Lebanon right now.
“The 'lucky ones' have been able to move in with family elsewhere in Lebanon or can afford to rent somewhere safer. More than 100,000 people have ended up in overcrowded shelters, and too many have had no choice but to sleep rough or stay in makeshift tents.
“I've seen for myself the damage in Lebanon caused by the destruction of entire apartment blocks following Israel's wars in the country in recent years. I saw the toll two months of constant bombing took on people's mental health as well as the financial strain of displacement.
“For a second time in as many years, our local partners have opened their doors to families in need of a hot meal and a shower after having to flee their homes. We need an immediate ceasefire to end this violence so that civilians can be kept safe and further loss of life prevented,” Bell added.