CAIRO (AP) --  The United States promised $212 million in immediate assistance to the devastated Gaza Strip on Sunday yet urged Palestinians and Israelis to return to peace negotiations to break a cycle of violence that has yielded three wars in six years.

People in Gaza "need our help desperately _ not tomorrow, not next week, but they need it now,'' U.S. Secretary of State John Kerry said at an international donor conference. He said more than 20,000 homes need to be rebuilt and 100,000 people remain displaced with winter fast approaching.

The Palestinians are seeking $4 billion in aid from donors at a conference in Cairo to rebuild Gaza after this summer's 50-day war between Hamas and Israel.

Kerry said the new U.S. money, which takes American aid to the Palestinians to more than $400 million this year, would go to security, economic development, food and medicine, shelter and water and sanitation projects.

Six months after the collapse of his Israeli-Palestinian mediation effort, the latest U.S. stab at forging a Mideast peace accord, Kerry renewed his call for a return to negotiations.

Kerry praised Egypt for organizing the conference, Israel for pledging to facilitate greater Palestinian economic opportunities and the U.N. for creating a monitoring system so that aid to Gaza isn't plundered by the militant group Hamas or used to threaten the Jewish state's security.

But Kerry said a lasting solution needs to be found and that the world doesn't want to see a return every two years or so to a war in Gaza, a cease-fire and another expensive reconstruction effort.

"A cease-fire is not peace,'' he said. "And we've got to find a way to get back to the table and help people make tough choices.''