No Gaza cease-fire deal is likely by Ramadan, Hamas leader says

Hamas' delegation has left Cairo.

Hamas' delegation has left Cairo, ending cease-fire talks between the militant group and Israel and making it unlikely that there will be a break in the violence before the religious month of Ramadan begins on March 10, Hamas leader Hussam Badran said in a statement.

While Israel signed off on a number of Hamas' terms, Hamas then ramped up its demands, insisting on a permanent cease-fire that retained its control of Gaza, two U.S. officials familiar with the talks said Wednesday.

Hamas said Israel's negative positions kept the Cairo negotiations from reaching an agreement.

U.S. Ambassador to Israel Jack Lew said at an event in Israel on Thursday that it's a "mistake" to think the hostage and cease-fire negotiation talks are over.

"There are still conversations going on. Still a back and forth. The differences are being narrowed. it’s still not an agreement," Lew said. "And everyone is looking towards Ramadan, which is coming closer."

"I can’t tell you it will be successful but it’s not yet the case that [the talks have] broken down," Lew said.

The U.S. has urged all parties in the negotiations to come to an agreement before Ramadan begins, but as the start of Ramadan grows closer, the possibility of having a deal by then looks less likely.

Officials said the U.S. and Israel narrowed their focus to what was previously described as phase one of a three-step pact: the exchange of several dozen hostages for at least six weeks of cease-fire. The officials said the "phase one" agreement would bring some of the most vulnerable hostages home, allow a dramatic increase of aid into Gaza and potentially cool tensions.

The ongoing war began after Hamas-led terrorists launched an unprecedented incursion into southern Israel from neighboring Gaza on Oct. 7. About 1,200 Israelis were killed while more than 200 others were taken hostage, according to Israeli authorities.

The Israeli military subsequently launched retaliatory airstrikes followed by a ground invasion of Gaza, killing more than 30,000 Palestinians, according to Gaza's Hamas-controlled Ministry of Health.

More than 100 hostages were released during a brief cease-fire agreement in late November in exchange for Palestinians held in Israeli prisons, but dozens more hostages have remained in captivity in the months since that truce ended.

ABC News' Nasser Atta and Shannon Crawford contributed to this report.