() Adam Boehler, the U.S. special envoy for hostage affairs, is urging Hamas to take a deal with Israel and release all remaining hostages to end the war.

The demand comes as Israeli forces moved deeper into central Gaza, an area that has been spared in the past because it is where several aid groups are based.

The U.S., Qatar, Israel and Egypt have all been waiting on a response from Hamas on the deal, which was presented last week. In its first phase, the proposal seeks the release of 10 living hostages and the bodies of 18 dead hostages.

Boehler said the negotiations in Qatar are “down to the details” at this point and that this proposal was a firm pathway to negotiate peace in the near future. There is a high priority for the U.S. to get the bodies of two American hostages, Itay Chen and Omer Neutra, back to the country.

“The Israelis want something done. Hamas is very hardheaded; they’ve been offered many things that they should take, and it’s time for Hamas to release the hostages,” Boehler said.

He added that he is “more optimistic” than before with the deal and said he now wants to see Hamas take action, warning that Israel may have to take “some sort of kinetic action” if the deal is not accepted.

The Israeli military launched a new ground offensive inside the Hamas stronghold city of Deir al-Balah on Sunday, making it the first time since Oct. 7 that troops were operating on the ground there. They issued a large evacuation for thousands of people who are taking refuge in that city.

Israeli forces have not operated in the city since then because of fears that some of the hostages were being held there.