Story highlights Israel and Hamas agree to a 12-hour cease-fire in Gaza starting Saturday morning

It's intended to be used for moving in medical supplies and taking out injured people

Americans are taking the lead on a text in consultation with Egyptians, sources say

Israel and Hamas agreed to a 12-hour cease-fire starting Saturday morning, temporarily halting more than two weeks of bloodshed that has claimed more than 900 mostly civilian lives.

Israeli Prime Minister Benjamin Netanyahu told Secretary of State John Kerry that Israel would agree to the truce, according to a U.S. official traveling with Kerry. And Palestinian parliament member Mustafa Barghouti said Hamas will comply.

"Of course, they will," Barghouti told CNN's "The Situation Room with Wolf Blitzer" Friday. "Not only Hamas but all Palestinians."

Both Barghouti and the chief Palestinian negotiator Saeb Erakat said Hamas was willing to sign on to a proposed seven-day cease-fire as well.

Kerry said Friday that Netanyahu was willing to go along with a temporary truce "as a good-faith down payment to move forward."

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Early Saturday, Israel Defense Forces warned in a statement that it will respond if militants attack its personnel or fire at Israeli civilians during the cease-fire that began at 8 a.m. local time (1 a.m. ET) Saturday. . During the cease-fire, the IDF will continue to carry out operations to "locate and neutralize" tunnels in Gaza, the statement said.

The Israeli Cabinet had earlier rejected a proposed one-week humanitarian cease-fire, but Kerry said no final proposal was submitted to Israel for a vote.

"Let's make that clear," Kerry told reporters in Cairo. "There is always mischief from people who oppose certain things, and I consider this one of those mischievous things."

U.N. Secretary-General Ban Ki-moon joined Kerry in efforts to reach a deal.

He called for a 12-hour humanitarian cease-fire, with the hope that it can be extended to seven days.

"Surely now, the parties must realize it is time for them to act," Ban said.

"My hope is that the 12 hours will be extended, perhaps to 24, and people will draw from that the good will and effort to find a solution," said Kerry, adding that he will travel to Paris on Saturday and continue to push for a deal.

The United States and Egypt were thought Friday to be moving closer to an agreement with Israel and the Palestinians on a one-week truce, starting Sunday.

Kerry met in Egypt with Ban and Egyptian Foreign Minister Sameh Shukri.

The Americans are taking the lead on drafting the text in consultation with Egyptians, the sources said.

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Palestinian Authority President Mahmoud Abbas is the main Palestinian party to the agreement and has been the lead in discussions with the United States, Egypt and Israel.

Qatar is the main conduit for talks with Hamas, along with Turkey, and sources said the United States is working with those two countries to try and get Hamas to sign on.

Key details of the plan are still under negotiation, the sources said, including an Israeli proposal for its troops to remain in Gaza during the one-week truce.

The temporary humanitarian cease-fire would be used to get medical supplies into Gaza, and the injured and some of the bodies out.

If that can be achieved, the parties hope they can enter formal negotiations on a more permanent truce that addresses economic, political and security concerns about Gaza, with other nations involved.

"The hope is that this could be used as an opening," another diplomatic source said.