TEL AVIV — Israel’s military offensive in Lebanon escalated Thursday with strikes hitting soldiers and medics and pummeling the southern suburbs of Beirut, as Lebanese authorities said 1.2 million people had been displaced by the fighting and Israeli forces ordered more villages to evacuate in the south.

The Lebanese Armed Forces, which is backed by the United States, said Israeli attacks killed two soldiers in separate incidents Thursday, including one on an army base that prompted Lebanese troops to return fire, raising fears the conflict could spiral. In the other, an Israeli attack killed a soldier as he was helping the Lebanese Red Cross evacuate villagers in southern Lebanon.