Netanyahu vowed to inflict a high price on the Yemeni group.
As the Israel-Hamas war continues, the latest round of cease-fire discussions appears to have reached an impasse.
Meanwhile, after six hostages were found dead in Gaza, protests erupted in Israel. Protesters have lashed out at Prime Minister Benjamin Netanyahu and demanded the government bring the hostages home.
The death toll in Gaza has passed 41,000 as of Tuesday, according to the Hamas-run Gaza Ministry of Health.
The ministry reported that 41,020 people have died and 94,925 have been injured since Israel launched its war against Hamas in Gaza on Oct. 8, 2023, following the Oct. 7 terrorist attacks.
That figure does not distinguish between civilians and combatants.
The Israel Defense Forces has released footage of the blood-stained tunnel where six hostages, including Israeli-American Hersh Goldberg-Polin, were held captive and murdered last month.
The "passageway" tunnel spanned 120 meters and was 20 meters deep, the IDF said.
The IDF estimates the hostages were in the tunnel for "weeks."
The Israeli military believes the six hostages were shot and killed on Aug. 29. The IDF said its soldiers found one of the tunnel’s shafts on Aug. 30, and the hostages’ bodies were discovered on Aug. 31.
The IDF said the hostages were killed with bullets from two guns.
The Hostages Families Forum Headquarters said in a statement that the "shocking" video "proves the unimaginable, inhuman conditions in which the 6 hostages Alex, Hersh, Eden, Ori, Carmel and Almog were held for months."
"Carmel, Hersh, Alex, Almog, Ori, and Eden suffered until their last breath. They begged to be released, pleaded for their lives," the group said. "Time is running out! That light, that hope, cannot die. A deal must be signed NOW!"
Secretary of State Antony Blinken said Tuesday that the IDF's initial report into the killing of U.S. citizen Aysenur Ezgi Eygi suggests "her killing was both unprovoked and unjustified."
"No one should be shot and killed for attending a protest. No one should have to put their life at risk just for freely expressing their views," Blinken said, using some of the strongest terms to condemn the killing by any American official yet.
"In our judgment, Israeli security forces need to make some fundamental changes in the way that they operate in the West Bank, including changes to their rules of engagement," Blinken continued, adding that the U.S. was well aware of longstanding allegations concerning Israeli authorities' use of excessive force against Palestinians in the West Bank.
"Now we have the second American citizen killed at the hands of Israeli security forces. It's not acceptable. It has to change, and we'll be making that clear to the senior-most members of the Israeli government," Blinken said.
"Now we're looking carefully at the results of this investigation, but even on an initial read and even accepting it at face value, it's clear that there are serious issues that need to be dealt with, and we will insist that they be dealt with," he added.
-ABC News' Shannon Kingston
The Israel Defense Forces (IDF) published the results of its initial inquiry into last week's killing of American Aysenur Ezgi Eygi in the West Bank.
"The inquiry found that it is highly likely that she was hit indirectly and unintentionally by IDF fire which was not aimed at her, but aimed at the key instigator of the riot," the IDF press release stated, referring to a period of reported unrest at the Beita Junction.
"Israel has sent a request to carry out an autopsy," it added. "The IDF expresses its deepest regret over the death of Aysenur Ezgi Eygi."
Eygi, 26, was a dual Turkish-American citizen and activist working for the International Solidarity Movement in the West Bank, working to protect local Palestinian farmers from attacks by Israeli settlers.
-ABC News' Matt Gutman and David Brennan
