CAIRO (AP) — With high hopes but low expectations, the U.S. stepped up calls Monday for an international push to end fighting in the Gaza Strip as President Barack Obama sent his top envoy to the Mideast to help broker a new cease-fire between Israel and Hamas militants — the third since 2009.

Voicing fresh concern about civilian casualties, Obama reaffirmed his belief that Israel has the right to defend itself against a barrage of more than 1,500 rockets being launched by Hamas.