"Prime Minister Najib Mikati and Humanitarian Coordinator for Lebanon Imran Riza today launched a $426 million flash appeal to mobilise urgent resources for civilians affected by the escalating conflict and resulting humanitarian crisis in Lebanon," the UN humanitarian agency OCHA said.

Lebanon's prime minister said Tuesday his country was facing "one of the most dangerous phases of its history", urging the United Nations to provide aid for one million people displaced by Israeli air strikes.

The statement comes hours after Israel launched a ground invasion of Lebanon early Tuesday, backed by air forces and artillery, marking the first time Israel has invaded Lebanon since 2006.

Since Monday, intense airstrikes across Lebanon's east, south and on southern Beirut have killed hundreds of people and forced many to flee their homes.

Mikati on Sunday said the Israeli attacks may have forced up to a million people to flee parts of Lebanon in possibly the worst displacement crisis in the tiny country's history.

Earlier this week, UN refugee chief Filippo Grandi said "well over 200,000 people are displaced inside Lebanon" and more than 50,000 had fled to neighbouring Syria.

*This story was edited by Ahram Online.