The agreement between Israel and Hamas announced Wednesday concerns the initial steps of a U.S.-backed framework for peace in Gaza -- but not the entirety of President Donald Trump’s sweeping 20-point plan unveiled last week.

Officials familiar with the negotiations say the talks have been almost singularly focused on what would happen in the initial few days and weeks of the deal: the partial Israeli withdrawal from Gaza and the exchange of the nearly 50 living and dead hostages for Palestinian prisoners.

Some of the most difficult points, such as the governance of Gaza and the disarmament of Hamas fighters, will still need to be negotiated down the line, officials say.

Still, there was building optimism through the week that talks were on the verge of a major breakthrough -- and the deal in principle on the first phase ultimately beat expectations. Some officials felt earlier that they would be lucky to get things tied up before the weekend.

It's not the first time, however, that the U.S. has brokered a multi-part agreement aimed at ending the conflict that includes the release of hostages in an initial phase.

At the beginning of the year, the Trump and Biden administrations, along with other mediators, brokered a three-phase agreement, which ultimately fell apart after the release of more than 30 hostages -- before negotiations on a second phase of the framework could truly get underway.

-ABC News' Shannon Kingston

Israeli Prime Minister Benjamin Netanyahu, calling it a "great day for Israel," said he will convene the Israeli government Thursday to "ratify" the ceasefire agreement and "bring all of our hostages home."

In a statement originally in Hebrew, Netanyahu thanked President Donald Trump for his "commitment to the sacred mission of freeing" the hostages.

-ABC News' Jordana Miller

Israeli Prime Minister Benjamin Netanyahu and President Donald Trump had a "very moving and warm conversation," and the two "congratulated each other on the historic achievement," over the phone, Netanyahu’s office said in a statement, originally in Hebrew.

Netanyahu invited Trump to address the Israeli parliament, the Knesset, Netanyahu’s office said in the statement.

"The Prime Minister thanked President Trump for all his efforts and his global leadership," the statement added.

-ABC News' Jordana Miller

In a statement following the announcement that both Israel and Hamas had agreed to the U.S.-brokered peace plan, Hamas said it is "stipulating an end to the war on Gaza."

Hamas called for President Donald Trump, as well as various Arab, Islamic and international parties, to "compel" Israel to "fully implement the agreement's requirements," including the withdrawal from the Gaza Strip, the entry of aid and a prisoner exchange.

Hamas thanked all mediators involved, including Trump, Qatar, Egypt and Turkey.

-ABC News' Diaa Ostaz