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."

Israeli forces mistakenly killed three Israeli hostages during combat in Shejaiya, Gaza, Israel Defense Forces spokesman Daniel Hagari said during a press briefing Friday.

The hostages were identified as: Yotam Haim, who was kidnapped from Kibbutz Kfar Aza; Samer Talalka, who was kidnapped from Kibbutz Nir Am; and Alon Shamriz, who was taken from Kibbutz Kfar Aza.

Israeli Prime Minister Benjamin Netanyahu called it “an unbearable tragedy.”

“The entire State of Israel will mourn this evening. My heart goes out to the grieving families in their difficult time,” he said.

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Israeli army mistakenly kills 3 hostages during combat in Gaza

The IDF said it’s reviewing the incident. The IDF said "immediate lessons from the event have been learned, which have been passed on to all IDF troops in the field."

Haim, 28, is survived by his parents, brother and sister, the Hostages and Missing Persons Families Forum said. He was a gifted musician, an animal lover and loved to cook Italian food, the forum said.

Shamriz, 26, lived in the Young Generation neighborhood of Kibbutz Kfar Aza, according to the forum.

Shamriz was slated to study computer engineering at Sapir College, the forum said.

"Alon's family and friends described him as a lover of life and a dedicated basketball fan. He played on the Sha'ar Hanegev basketball team," the forum said in a statement.

National Security Council spokesperson John Kirby called the incident "heartbreaking" and a "tragic mistake," adding it is not particularly a reflection of Israeli’s ability to be precise.

National Security Council spokesperson John Kirby said conversations with the Israelis about transitioning to lower intensity military operations have been "constructive."

"There’s a general agreement that a transition to lower intensity operations obviously is going to be an important next step here," Kirby said. "The idea of transitioning into different phases is certainly a common practice among militaries as they conduct operations of this kind."

-ABC News' Selina Wang

Al Jazeera cameraman Samer Abu Daqqa died in Gaza after he was struck and injured during combat in the region, ABC News has confirmed. He died at the scene before an ambulance could reach him.

Al Jazeera said its correspondent, Wael al-Dahdouh, was injured from shrapnel in the same incident.

Sixty-five journalists have been killed since the start of the Israel-Hamas war, according to the Committee to Protect Journalists.

-ABC News' Nasser Atta and Sami Zayara

Twenty Israeli soldiers have been killed by accident in the Gaza Strip since the start of the war, most by friendly fire, according to the Israel Defense Forces.

The IDF confirmed to ABC News on Tuesday that a total of 105 soldiers have died since ground operations were launched in Gaza, 20 of which were considered accidents. Of those 20 accidental deaths, 13 were due to friendly fire, one was caused by firing irregularities and six were accidents involving weaponry, machinery or trampling, according to the IDF.

-ABC News' Dana Savir