Feb. 25 (UPI) — Negotiators meeting Paris have agreed on the basics of a deal under which the Palestinian militant group Hamas would release remaining Israeli hostages in exchange for a cease-fire, a top U.S. official said Sunday.

U.S. National Security Adviser Jake Sullivan told CNN’s State of the Union that meetings in the French capital involving Israel, the United States, Egypt and Qatar, which wrapped up Saturday, have resulted in an agreement on what the “basic contours” of a hostage deal in exchange for a temporary cease-fire in Gaza “would look like.”

Sullivan cautioned the details are still being “hammered out” as Egypt and Qatar work indirectly with Hamas on the proposed agreement, and emphasized it will ultimately be up to the Palestinians to release the Israeli hostages.

“That work is underway and we hope that in the coming days we can drive to a point where there is actually a firm and final agreement on this issue, but we will have to wait and see,” he said.

When asked if he was “hopeful” the negotiations could result in a hostage release and a cease-fire in the conflict, the U.S. official declined to make any predictions.

“The United States’ position in this clear,” he said. “We would like to see this deal get done, we would like to see the hostages returned, including American hostages.”

After the Israeli delegation returned from Paris on Saturday, the country’s war cabinet subsequently agreed to continue the efforts aimed at freeing about 130 hostages by sending another negotiating team to Qatar, local media reported.

According to Israeli daily Yedioth Ahronot, reports indicated the proposed deal’s outline calls for an initial humanitarian release of 35 to 40 children, women, elderly and sick hostages, with Israel seeking to include female IDF soldiers in the release.

In exchange, Israel would agree to a weeks-long cease-fire without committing to ending the war, during which time the mediators would seek to extend it while negotiating for a larger hostage deal.

Also to be discussed is the timeline for the withdrawal of the Israel Defense Forces from Gaza, beginning with northern section of the Strip, where Hamas is reportedly demanding that displaced Gazans be allowed to return to their homes.

Hamas officials, however, did not appear to be especially optimistic about the state of the talks in comments made on Saturday, reiterating they have not dropped their demands for Israel to withdraw all of its forces from Gaza as a condition for the release of hostages.

Senior Hamas official Mahmoud al-Mardawi on Saturday told the Lebanese news site Al Mayadeen the militant group has yet to receive anything from the Paris cease-fire mediators.

The government of Israeli Prime Minister Benjamin Netanyahu “still adopts an intransigent stance toward the demands of the resistance, and its goals clash with all the initiatives proposed,” he said.

The publication also cited Hamas sources as saying Israel is continuing to reject its key demand of a Gaza withdrawal, calling it “unfeasible” while insisting on its own conditions that do not include a withdrawal or a permanent cease-fire.