Israel-Gaza live updates: IDF says it's discovered one of Hamas' biggest tunnels

Israel Defense Forces claimed on Sunday that it has discovered one of Hamas' biggest tunnels under the Gaza Strip and that it plans to destroy it.

Measuring nearly 2 1/2 miles long and large enough to drive a vehicle through, the tunnel's entrance was located roughly 1,300 feet from the Erez border crossing between Gaza and Israel, the IDF said in a post on the social media site X.

The shaft, constructed with reinforced concrete and reaching a depth of more than 160 feet, is believed to have taken years to build and millions of dollars to complete, according to the IDF. The tunnel is also equipped with electricity, communications networks and rails, according to the IDF.

It's unclear when the tunnel was found. The IDF said it also found weapons, militants and booby traps in the tunnel.

The tunnel, according to the IDF, is the brainchild of Mohammed Sinwar, the brother of Hamas leader Yahya Sinwar. The IDF released a Hamas video it seized showing Mohammed Sinwar in the passenger seat of a Jeep driving inside the tunnel.

IDF spokesperson Daniel Hagari told reporters that the tunnel would be destroyed.

"Without demolishing the tunnel project of Hamas, we cannot demolish Hamas," Hagari said.

The IDF claims to have destroyed more than 800 tunnels in Gaza since the beginning of the war.

ABC News' Ines De La Cuetara

The Israel Defense Forces commander said the accidental shooting this week of three Israeli hostages in Gaza was "against the rules of engagement."

The three hostages "did everything possible so that we would understand -- they moved around shirtless so that we wouldn't suspect them of carrying explosives and they held a white cloth, but the tension overcame all of the above," Lt. Gen. Herzi Halevi said in a video statement Saturday.

He noted that the shooting of someone who raises a white flag and seeks to surrender "is forbidden."

"However, this shooting was carried out during combat and under pressure," Halevi added. "There may be additional cases in which hostages escape or are abandoned during combat, and we have the duty and responsibility to rescue them alive."

Halevi said he and the IDF are responsible for what happened and "will do everything to prevent such incidents from recurring in future combat."

-ABC News' Dorit Long

Inbar Hayman, an Israeli hostage who was captured at the Re'im music festival, was killed in Hamas captivity, Israeli government spokesperson Eylon Levy said Saturday.

Hayman, 27, ran from the festival with two friends but was caught by "terrorists riding motorcycles," the Hostages and Missing Persons Families Forum said in a statement Saturday.

-ABC News' Dorit Long

The Israel Defense Forces released information regarding its preliminary investigation into the killing of hostages, saying that the incident took place in an area of "very intense fighting."

The three hostages came out of a building -- a few meters from the troops -- without shirts, carrying a stick with white cloth. A soldier saw them as a threat and opened fire, killing two hostages instantly, according to an IDF spokesperson.

The third was injured and ran back into the building where all three emerged from and someone cried "help" in Hebrew. At this point, the battalion commander ordered his troops to stop firing. But, despite the order, another burst was fired, killing the third hostage, according to an IDF spokesperson.

The three men killed have been identified as 28-year old Yotam Haim; 26-year old Alon Shamriz; and 22-year old Samer Talalka.

The IDF said the three hostages were ‘mistakenly identified’ as a threat. Israeli Prime Minister Benjamin Netanyahu called the incident an "unbearable tragedy."