The fear has been building for weeks.

More than one million Palestinians fled into Rafah, the southernmost region of Gaza, hoping to escape the war. Now, Israel has threatened to extend its invasion there, too.

Amid days filled with struggles to secure food, water and shelter, uncertainty has dominated people’s conversations, said Khalid Shurrab, a charity worker staying with his family in a leaky tent in Rafah.

“We have two options, either to stay as we are or face our destiny — death,” said Mr. Shurrab, 36. “People literally have no other safe place to go.”

Rafah, which so far had been spared the brunt of Israel’s onslaught, has become a new focal point of a war now in its sixth month. It is where most of Gaza’s 2.2 million people have ended up, multiplying the area’s population and exhausting its limited resources.

And now, with Israel signaling its intent to go after Hamas militants in Rafah, and Egypt blocking most Gazans from crossing its border to the south, families fear they are trapped.