U.S. Secretary of State John Kerry is hoping to get international support for a Mideast cease-fire. But he acknowledges the differences between Israel and Hamas run very deep and must be addressed in any long-term solution.

The U.S. stepped up calls Monday for a global push to end fighting in the Gaza Strip as Kerry tried to help broker a new cease-fire between Israel and Hamas militants — the third since 2009. But he said those underlying issues must be confronted.

President Barack Obama, meanwhile, is trying a delicate balancing act on the Mideast conflict. Obama reaffirmed his belief that Israel has the right to defend itself against a barrage of more than 1,500 rockets launched by Hamas, while voicing fresh concern about civilian casualties.