Hezbollah militants fired rockets at Israeli towns and fought ground battles with Israeli troops in southern Lebanon on Wednesday, as the United Nations warned that nearly a million Lebanese had fled the spreading war between Israel and Iranian-backed groups in the Middle East.

In a sign of the war’s growing scale, Israeli evacuation orders now cover a quarter of Lebanon’s land area, according to the United Nations, which says the calls have sent people fleeing from more than a hundred villages and urban areas.

“To the people of South Lebanon: Be careful!” an Israeli military spokesman, Avichay Adraee, said on Wednesday in an Arabic language warning posted online. Israeli forces, he said, were continuing “to attack Hezbollah sites in and near your village, and for your own safety you are prohibited from returning to your homes until further notice.”

More than 600,000 people of Lebanon’s 5.4 million have been displaced within the country, threatening to overwhelm shelters, U.N. officials warned, and 300,000 others have fled abroad. Half of Lebanon’s public schools have been turned into shelters, the aid group Save the Children said on Wednesday.

Displaced people have set up tents on white-sand beaches where vacationers once sunbathed, and people have taken refuge not only in schools but in parks, unfinished buildings and at least one nightclub.