The mother and uncle of an American servicemember were rescued from Gaza in an operation involving Israel and Egypt -- the first known mission of its kind to take place since the war broke out -- U.S. officials confirmed on Thursday.

Zahra Sckak and her brother-in-law, Farid (a U.S. citizen), were shepherded out of Gaza days ago, though the details of the operation were kept quiet due to security concerns surrounding the operation.

The U.S. played a "liaison role" in the case, according to State Department spokesperson Matthew Miller.

"There wasn’t an operational presence by any U.S. forces or U.S. personnel there to help these family members escape, but we were glad to see them make their way safely out of Gaza and we’ll continue to work to do what we can to facilitate the departure of others," Miller told reporters Thursday.

Fadi Sckak, a brother of the U.S. servicemember, told ABC News Live last month that his mother was on the list of individuals approved to leave Gaza through the Rafah gate, but that she couldn't get to the border crossing because of the heavy fighting surrounding the area where she was sheltering.

-ABC News' Shannon K. Crawford

Three Israeli citizens previously considered missing are now recognized as hostages, Israel Defense Forces spokesperson Rear Adm. Daniel Hagari said Thursday.

"This decision was made following the completion of search and investigation operations in Israel and after examining all plausible scenarios and the information we have," he said during a briefing.

That brings the total number of Israeli hostages held in Gaza to 136, including 23 believed to be dead, officials said.

-ABC News' Jordana Miller

U.S. Secretary of State Antony Blinken will be making a marathon trip to the Middle East -- his fourth visit to the region since the Oct. 7 attack, the State Department announced Thursday.

The trip, running from Jan. 4 to 11, will technically be his fifth visit to Israel since the war began; he stopped there twice on his trip in October.

"Throughout his trip, the Secretary will underscore the importance of protecting civilian lives in Israel and the West Bank and Gaza; securing the release of all remaining hostages; our shared commitment to facilitating the increased, sustained delivery of life-saving humanitarian assistance to civilians in Gaza and the resumption of essential services; and ensuring that Palestinians are not forcibly displaced from Gaza," State Department Spokesperson Matt Miller said in a statement.

The last part of the agenda Miller lays out -- "ensuring that Palestinians are not forcibly displaced from Gaza" -- runs counter to the rhetoric put forth in recent days by Israeli Minister of National Security Ben Gvir and other far-right politicians, comments the Biden administration have already denounced.

"We don't expect every conversation on this trip to be easy. There are obviously tough issues facing the region and difficult choices ahead," Miller said in a briefing Thursday afternoon, adding that the U.S. intends to "tackle them head on."

As of now, Blinken is scheduled to spend time in eight countries: Turkey, Greece, Jordan, Qatar, the United Arab Emirates, Saudi Arabia, Israel and Egypt. He will also be stopping in the West Bank.

"The secretary believes we need to try to make progress on getting humanitarian access in," Miller said. "The secretary believes we need to make progress on minimizing harm to Palestinian civilians. He believes we need to make progress on continuing to try to keep the conflict from escalating, which is why he is returning to the region."

-ABC News' Shannon Crawford

The leader of Yemen's Iran-backed Houthi rebel group has called for mass protests to take place on Friday against Israel's ongoing war in the Gaza Strip.

"Let the dear Yemeni people make their voice and word heard to the whole world, in their steadfastness in their faith, moral and humanitarian stance in supporting the oppressed Palestinian people, against whom the Jewish Zionists are committing crimes of genocide, completely destroying their cities and homes in Gaza, and are creative in practicing the most heinous crimes against them, such as burying the living and crushing them," Houthi leader Abdul Malik Badr al-Din al-Houthi said in a statement on Thursday.

Houthi rebels, who have been at war with Yemen's internationally recognized government since 2014 and currently control a large part of the country, have carried out attacks on ships in the Red Sea in recent weeks in response to Israel's offensive in Gaza, a territory ruled by Iran-backed Palestinian militant group Hamas.

-ABC News' Will Gretsky and Morgan Winsor

In 10 posts on X, formerly known as Twitter, in 10 different languages, Israeli President Isaac Herzog issued a New Year's call to world leaders and people around the globe to advance the immediate return of the hostages being held by Hamas in Gaza.

"As we enter 2024, I call on the entire family of nations, on all world leaders, to demand and work for the immediate, unconditional release of our 133 hostages," he wrote Sunday.

"Their immediate release is at the core of our battle with Hamas terrorists in Gaza," he added.

According to the Israeli prime minister's office, there are 129 hostages being held by Hamas -- including at least 23 people believed to be dead whose bodies are still being held in Gaza.

-ABC News' Edward Szekeres