Flares light up the sky over Gaza City, Friday August 1. Israeli Prime Minister Benjamin Netanyahu said Thursday that Israel will destroy Hamas’ tunnel network in the Gaza Strip designed for deadly attacks inside Israel, “with or without a cease-fire.” Israel expanded what started July 8 as an aerial campaign against Hamas and widened it into a ground offensive on July 17. Since then, Israel says the campaign has concentrated on destroying cross-border tunnels militants constructed to carry out attacks inside Israeli territory and ending rocket attacks on its cities. (AP Photo/Dusan Vranic)

GAZA STRIP — A three-day cease-fire in the Gaza Strip has gone into effect following heavy Israel-Hamas fighting.

The cease-fire, announced hours earlier by the U.S. and the U.N., took effect at 8:00 a.m. (0500 GMT) Friday. Secretary of State John Kerry cautioned there were “no guarantees” that the lull would bring an end to the Gaza war, now in its fourth week.

Israel and Hamas both said they would respect the cease-fire but would respond to attacks.

At least four short humanitarian cease-fires have been announced since the conflict began, but each has been broken within a few hours by renewed fighting.

Hours before the cease-fire was to take effect, 17 Palestinians were killed in Israeli strikes. Israel’s military said five soldiers were killed along the Gaza border the previous evening.

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